Release 1.33.0

Exclude SCM and CI files from distribution

.appveyor.yml

@@ -0,0 +1,21 @@
+environment:
+  matrix:
+  - TOXENV: "py27-pytestlatest"
+  - TOXENV: "py35-pytestlatest"
+  - TOXENV: "py36-pytestlatest"
+  - TOXENV: "py37-pytestlatest"
+  - TOXENV: "py38-pytestlatest"
+  - TOXENV: "py38-pytestmaster"
+
+install:
+  - C:\Python38\python -m pip install -U pip setuptools virtualenv
+  - C:\Python38\python -m pip install -U tox setuptools_scm
+
+build: false  # Not a C# project, build stuff at the test step instead.
+
+test_script:
+  - C:\Python38\python -m tox
+
+# We don't deploy anything on tags with AppVeyor, we use Travis instead, so we
+# might as well save resources
+skip_tags: true

.gitignore

@@ -23,7 +23,7 @@ include/
 lib/
 bin/
 env/
-xdist/_version.py*
+src/xdist/_version.py*
 pytest_xdist.egg-info
 issue/
 3rdparty/

.pre-commit-config.yaml

@@ -1,12 +1,12 @@
 repos:
 -   repo: https://github.com/ambv/black
-    rev: 18.6b4
+    rev: 19.10b0
     hooks:
     -   id: black
         args: [--safe, --quiet]
-        language_version: python3.6
+        language_version: python3.7
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v1.3.0
+    rev: v2.4.0
     hooks:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer
@@ -21,4 +21,4 @@ repos:
         files: ^(CHANGELOG.rst|HOWTORELEASE.rst|README.rst|changelog/.*)$
         language: python
         additional_dependencies: [pygments, restructuredtext_lint]
-        python_version: python3.6
+        language_version: python3.7

.travis.yml

@@ -1,56 +1,52 @@
-sudo: false
+dist: xenial
 language: python
 
 notifications:
   irc:
     channels:
-    - 'chat.freenode.net#pytest'
+      - 'chat.freenode.net#pytest'
     on_success: change
     on_failure: change
     skip_join: true
   email:
   - pytest-commit@python.org
 
-python:
-- '2.7'
-- '3.4'
-- '3.5'
-- '3.6'
-env:
-- TOXENV=py-pytest30
-- TOXENV=py-pytest31
-- TOXENV=py-pytest32
-- TOXENV=py-pytest33
-- TOXENV=py-pytest36
-
-install: pip install tox setuptools_scm
+install:
+  - pip install -U pip setuptools
+  - pip install tox setuptools_scm
 script: tox
 
 stages:
-- linting
-- test
-- name: deploy
-  if: repo = pytest-dev/pytest-xdist AND tag IS present
+  - baseline
+  - test
+  - name: deploy
+    if: repo = pytest-dev/pytest-xdist AND tag IS present
 
 jobs:
   include:
-    - stage: linting
-      python: '3.6'
-      script:
-      - tox -e linting
+    - stage: baseline
+      python: '3.7'
+      env: TOXENV=linting
+      cache:
+        directories:
+          - $HOME/.cache/pre-commit
+    - python: '3.8'
+      env: TOXENV=py38-pytestlatest
+    - python: '2.7'
+      env: TOXENV=py27-pytestlatest
+
     - stage: test
-    # python x env above are already included into this stage
-    - python: "2.7"
-      env: TOXENV=py27-pytestmaster
-    - python: "2.7"
-      env: TOXENV=py27-pytestfeatures
+      python: "3.5"
+      env: TOXENV=py35-pytestlatest
     - python: "3.6"
-      env: TOXENV=py36-pytestmaster
-    - python: "3.6"
-      env: TOXENV=py36-pytestfeatures
+      env: TOXENV=py36-pytestlatest
+    - python: "3.7"
+      env: TOXENV=py37-pytestlatest
+    - python: "3.8"
+      env: TOXENV=py38-pytestmaster
 
     - stage: deploy
-      python: '3.6'
+      python: '3.8'
       env:
       install: pip install -U setuptools setuptools_scm
       script: skip

CHANGELOG.rst

@@ -1,3 +1,218 @@
+pytest-xdist 1.33.0 (2020-07-09)
+================================
+
+Features
+--------
+
+- `#554 <https://github.com/pytest-dev/pytest-xdist/issues/554>`_: Fix warnings support for upcoming pytest 6.0.
+
+
+Trivial Changes
+---------------
+
+- `#548 <https://github.com/pytest-dev/pytest-xdist/issues/548>`_: SCM and CI files are no longer included in the source distribution.
+
+
+pytest-xdist 1.32.0 (2020-05-03)
+================================
+
+Deprecations and Removals
+-------------------------
+
+- `#475 <https://github.com/pytest-dev/pytest-xdist/issues/475>`_: Drop support for EOL Python 3.4.
+
+
+Features
+--------
+
+- `#524 <https://github.com/pytest-dev/pytest-xdist/issues/524>`_: Add `testrun_uid` fixture. This is a shared value that uniquely identifies a test run among all workers.
+  This also adds a `PYTEST_XDIST_TESTRUNUID` environment variable that is accessible within a test as well as a command line option `--testrunuid` to manually set the value from outside.
+
+
+pytest-xdist 1.31.0 (2019-12-19)
+================================
+
+Features
+--------
+
+- `#486 <https://github.com/pytest-dev/pytest-xdist/issues/486>`_: Add support for Python 3.8.
+
+
+Bug Fixes
+---------
+
+- `#491 <https://github.com/pytest-dev/pytest-xdist/issues/491>`_: Fix regression that caused custom plugin command-line arguments to be discarded when using ``--tx`` mode.
+
+
+
+pytest-xdist 1.30.0 (2019-10-01)
+================================
+
+Features
+--------
+
+- `#448 <https://github.com/pytest-dev/pytest-xdist/issues/448>`_: Initialization between workers and master nodes is now more consistent, which fixes a number of
+  long-standing issues related to startup with the ``-c`` option.
+
+  Issues:
+
+  * `#6 <https://github.com/pytest-dev/pytest-xdist/issues/6>`__: Poor interaction between ``-n#`` and ``-c X.cfg``
+  * `#445 <https://github.com/pytest-dev/pytest-xdist/issues/445>`__: pytest-xdist is not reporting the same nodeid as pytest does
+
+  This however only works with **pytest 5.1 or later**, as it required changes in pytest itself.
+
+
+Bug Fixes
+---------
+
+- `#467 <https://github.com/pytest-dev/pytest-xdist/issues/467>`_: Fix crash issues related to running xdist with the terminal plugin disabled.
+
+
+pytest-xdist 1.29.0 (2019-06-14)
+================================
+
+Features
+--------
+
+- `#226 <https://github.com/pytest-dev/pytest-xdist/issues/226>`_: ``--max-worker-restart`` now assumes a more reasonable value (4 times the number of
+  nodes) when not given explicitly. This prevents test suites from running forever when the suite crashes during collection.
+
+- `#435 <https://github.com/pytest-dev/pytest-xdist/issues/435>`_: When the test session is interrupted due to running out of workers, the reason is shown in the test summary
+  for easier viewing.
+
+- `#442 <https://github.com/pytest-dev/pytest-xdist/issues/442>`_: Compatibility fix for upcoming pytest 5.0: ``session.exitstatus`` is now an ``IntEnum`` object.
+
+
+Bug Fixes
+---------
+
+- `#435 <https://github.com/pytest-dev/pytest-xdist/issues/435>`_: No longer show an internal error when we run out of workers due to crashes.
+
+
+pytest-xdist 1.28.0 (2019-04-02)
+================================
+
+Features
+--------
+
+- `#426 <https://github.com/pytest-dev/pytest-xdist/issues/426>`_: ``pytest-xdist`` now uses the new ``pytest_report_to_serializable`` and ``pytest_report_from_serializable``
+  hooks from ``pytest 4.4`` (still experimental). This will make report serialization more reliable and
+  extensible.
+
+  This also means that ``pytest-xdist`` now requires ``pytest>=4.4``.
+
+
+pytest-xdist 1.27.0 (2019-02-15)
+================================
+
+Features
+--------
+
+- `#374 <https://github.com/pytest-dev/pytest-xdist/issues/374>`_: The new ``pytest_xdist_getremotemodule`` hook allows overriding the module run on remote nodes.
+
+- `#415 <https://github.com/pytest-dev/pytest-xdist/issues/415>`_: Improve behavior of ``--numprocesses=auto`` to work well with ``--pdb`` option.
+
+
+pytest-xdist 1.26.1 (2019-01-28)
+================================
+
+Bug Fixes
+---------
+
+- `#406 <https://github.com/pytest-dev/pytest-xdist/issues/406>`_: Do not implement deprecated ``pytest_logwarning`` hook in pytest versions where it is deprecated.
+
+
+pytest-xdist 1.26.0 (2019-01-11)
+================================
+
+Features
+--------
+
+- `#376 <https://github.com/pytest-dev/pytest-xdist/issues/376>`_: The current directory is no longer added ``sys.path`` for local workers, only for remote connections.
+
+  This behavior is surprising because it makes xdist runs and non-xdist runs to potentially behave differently.
+
+
+Bug Fixes
+---------
+
+- `#379 <https://github.com/pytest-dev/pytest-xdist/issues/379>`_: Warning attributes are checked to make sure they can be dumped prior to
+  serializing the warning for submission to the master node.
+
+
+pytest-xdist 1.25.0 (2018-12-12)
+================================
+
+Deprecations and Removals
+-------------------------
+
+- `#372 <https://github.com/pytest-dev/pytest-xdist/issues/372>`_: Pytest versions older than 3.6 are no longer supported.
+
+
+Features
+--------
+
+- `#373 <https://github.com/pytest-dev/pytest-xdist/issues/373>`_: Node setup information is hidden when pytest is run in quiet mode to reduce noise on many-core machines.
+
+- `#388 <https://github.com/pytest-dev/pytest-xdist/issues/388>`_: ``mainargv`` is made available in ``workerinput`` from the host's ``sys.argv``.
+
+  This can be used via ``request.config.workerinput["mainargv"]``.
+
+
+Bug Fixes
+---------
+
+- `#332 <https://github.com/pytest-dev/pytest-xdist/issues/332>`_: Fix report of module-level skips (``pytest.skip(reason, allow_module_level=True)``).
+
+- `#378 <https://github.com/pytest-dev/pytest-xdist/issues/378>`_: Fix support for gevent monkeypatching
+
+- `#384 <https://github.com/pytest-dev/pytest-xdist/issues/384>`_: pytest 4.1 support: ``ExceptionInfo`` API changes.
+
+- `#390 <https://github.com/pytest-dev/pytest-xdist/issues/390>`_: pytest 4.1 support: ``pytest_logwarning`` hook removed.
+
+
+pytest-xdist 1.24.1 (2018-11-09)
+================================
+
+Bug Fixes
+---------
+
+- `#349 <https://github.com/pytest-dev/pytest-xdist/issues/349>`_: Correctly handle warnings created with arguments that can't be serialized during the transfer from workers to master node.
+
+
+pytest-xdist 1.24.0 (2018-10-18)
+================================
+
+Features
+--------
+
+- `#337 <https://github.com/pytest-dev/pytest-xdist/issues/337>`_: New ``--maxprocesses`` command-line option that limits the maximum number of workers when using ``--numprocesses=auto``.
+
+
+Bug Fixes
+---------
+
+- `#351 <https://github.com/pytest-dev/pytest-xdist/issues/351>`_: Fix scheduling deadlock in case of inter-test locking.
+
+
+pytest-xdist 1.23.2 (2018-09-28)
+================================
+
+Bug Fixes
+---------
+
+- `#344 <https://github.com/pytest-dev/pytest-xdist/issues/344>`_: Fix issue where Warnings could cause pytest to fail if they do not set the args attribute correctly.
+
+
+pytest-xdist 1.23.1 (2018-09-25)
+================================
+
+Bug Fixes
+---------
+
+- `#341 <https://github.com/pytest-dev/pytest-xdist/issues/341>`_: Fix warnings transfer between workers and master node with pytest >= 3.8.
+
+
 pytest-xdist 1.23.0 (2018-08-23)
 ================================
 
@@ -256,17 +471,6 @@ Improved Documentation
 - Added ``HOWTORELEASE`` documentation. (#155)
 
 
-..
-    You should *NOT* be adding new change log entries to this file, this
-    file is managed by towncrier. You *may* edit previous change logs to
-    fix problems like typo corrections or such.
-    To add a new change log entry, please see
-    https://pip.pypa.io/en/latest/development/#adding-a-news-entry
-    We named the news folder ``changelog``
-
-.. towncrier release notes start
-
-
 1.17.0
 ------
 

MANIFEST.in

@@ -0,0 +1,5 @@
+exclude .appveyor.yml
+exclude .gitignore
+exclude .pre-commit-config.yaml
+exclude .travis.yml
+prune .github

README.rst

@@ -95,6 +95,59 @@ any guaranteed order, but you can control this with these options:
   in version ``1.21``.
 
 
+Making session-scoped fixtures execute only once
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+``pytest-xdist`` is designed so that each worker process will perform its own collection and execute
+a subset of all tests. This means that tests in different processes requesting a high-level
+scoped fixture (for example ``session``) will execute the fixture code more than once, which
+breaks expectations and might be undesired in certain situations.
+
+While ``pytest-xdist`` does not have a builtin support for ensuring a session-scoped fixture is
+executed exactly once, this can be achieved by using a lock file for inter-process communication.
+
+The example below needs to execute the fixture ``session_data`` only once (because it is
+resource intensive, or needs to execute only once to define configuration options, etc), so it makes
+use of a `FileLock <https://pypi.org/project/filelock/>`_ to produce the fixture data only once
+when the first process requests the fixture, while the other processes will then read
+the data from a file.
+
+Here is the code:
+
+.. code-block:: python
+
+    import json
+
+    import pytest
+    from filelock import FileLock
+
+
+    @pytest.fixture(scope="session")
+    def session_data(tmp_path_factory, worker_id):
+        if not worker_id:
+            # not executing in with multiple workers, just produce the data and let
+            # pytest's fixture caching do its job
+            return produce_expensive_data()
+
+        # get the temp directory shared by all workers
+        root_tmp_dir = tmp_path_factory.getbasetemp().parent
+
+        fn = root_tmp_dir / "data.json"
+        with FileLock(str(fn) + ".lock"):
+            if fn.is_file():
+                data = json.loads(fn.read_text())
+            else:
+                data = produce_expensive_data()
+                fn.write_text(json.dumps(data))
+        return data
+
+
+The example above can also be use in cases a fixture needs to execute exactly once per test session, like
+initializing a database service and populating initial tables.
+
+This technique might not work for every case, but should be a starting point for many situations
+where executing a high-scope fixture exactly once is important.
+
 Running tests in a Python subprocess
 ------------------------------------
 
@@ -224,6 +277,47 @@ The information about the worker_id in a test is stored in the ``TestReport`` as
 well, under the ``worker_id`` attribute.
 
 
+Uniquely identifying the current test run
+-----------------------------------------
+
+*New in version 1.32.*
+
+If you need to globally distinguish one test run from others in your
+workers, you can use the ``testrun_uid`` fixture. For instance, let's say you
+wanted to create a separate database for each test run:
+
+.. code-block:: python
+
+    import pytest
+    from posix_ipc import Semaphore, O_CREAT
+
+    @pytest.fixture(scope="session", autouse=True)
+    def create_unique_database(testrun_uid):
+        """ create a unique database for this particular test run """
+        database_url = f"psql://myapp-{testrun_uid}"
+
+        with Semaphore(f"/{testrun_uid}-lock", flags=O_CREAT, initial_value=1):
+            if not database_exists(database_url):
+                create_database(database_url)
+
+    @pytest.fixture()
+    def db(testrun_uid):
+        """ retrieve unique database """
+        database_url = f"psql://myapp-{testrun_uid}"
+        return database_get_instance(database_url)
+
+
+Additionally, during a test run, the following environment variable is defined:
+
+* ``PYTEST_XDIST_TESTRUNUID``: the unique id of the test run.
+
+Accessing ``sys.argv`` from the master node in workers
+------------------------------------------------------
+
+To access the ``sys.argv`` passed to the command-line of the master node, use
+``request.config.workerinput["mainargv"]``.
+
+
 Specifying test exec environments in an ini file
 ------------------------------------------------
 

appveyor.yml

@@ -1,22 +0,0 @@
-environment:
-  matrix:
-  # note: please use "tox --listenvs" to populate the build matrix
-  - TOXENV: "py27-pytest33"
-  - TOXENV: "py34-pytest33"
-  - TOXENV: "py35-pytest33"
-  - TOXENV: "py36-pytest33"
-  - TOXENV: "py36-pytest36"
-  - TOXENV: "py27-pytest33-pexpect"
-  - TOXENV: "py36-pytest33-pexpect"
-
-install:
-  - C:\Python36\python -m pip install -U tox setuptools_scm pip
-
-build: false  # Not a C# project, build stuff at the test step instead.
-
-test_script:
-  - C:\Python36\python -m tox
-
-# We don't deploy anything on tags with AppVeyor, we use Travis instead, so we
-# might as well save resources
-skip_tags: true

setup.py

@@ -1,25 +1,30 @@
 from setuptools import setup, find_packages
 
-install_requires = ["execnet>=1.1", "pytest>=3.0.0", "pytest-forked", "six"]
+install_requires = ["execnet>=1.1", "pytest>=4.4.0", "pytest-forked", "six"]
 
 
+with open("README.rst") as f:
+    long_description = f.read()
+
 setup(
     name="pytest-xdist",
-    use_scm_version={"write_to": "xdist/_version.py"},
+    use_scm_version={"write_to": "src/xdist/_version.py"},
     description="pytest xdist plugin for distributed testing"
     " and loop-on-failing modes",
-    long_description=open("README.rst").read(),
+    long_description=long_description,
     license="MIT",
     author="holger krekel and contributors",
     author_email="pytest-dev@python.org,holger@merlinux.eu",
     url="https://github.com/pytest-dev/pytest-xdist",
     platforms=["linux", "osx", "win32"],
-    packages=find_packages(exclude=["testing", "example"]),
+    packages=find_packages(where="src"),
+    package_dir={"": "src"},
+    extras_require={"testing": ["filelock"]},
     entry_points={
         "pytest11": ["xdist = xdist.plugin", "xdist.looponfail = xdist.looponfail"]
     },
     zip_safe=False,
-    python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
+    python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*",
     install_requires=install_requires,
     setup_requires=["setuptools_scm"],
     classifiers=[
@@ -37,8 +42,9 @@ setup(
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
     ],
 )

src/xdist/dsession.py

@@ -46,14 +46,11 @@ class DSession(object):
         self._failed_collection_errors = {}
         self._active_nodes = set()
         self._failed_nodes_count = 0
-        self._max_worker_restart = self.config.option.maxworkerrestart
-        if self._max_worker_restart is not None:
-            self._max_worker_restart = int(self._max_worker_restart)
-        try:
-            self.terminal = config.pluginmanager.getplugin("terminalreporter")
-        except KeyError:
-            self.terminal = None
-        else:
+        self._max_worker_restart = get_default_max_worker_restart(self.config)
+        # summary message to print at the end of the session
+        self._summary_report = None
+        self.terminal = config.pluginmanager.getplugin("terminalreporter")
+        if self.terminal:
             self.trdist = TerminalDistReporter(config)
             config.pluginmanager.register(self.trdist, "terminaldistreporter")
 
@@ -172,7 +169,7 @@ class DSession(object):
         """
         self.config.hook.pytest_testnodedown(node=node, error=None)
         if node.workeroutput["exitstatus"] == 2:  # keyboard-interrupt
-            self.shouldstop = "%s received keyboard-interrupt" % (node,)
+            self.shouldstop = "{} received keyboard-interrupt".format(node)
             self.worker_errordown(node, "keyboard-interrupt")
             return
         if node in self.sched.nodes:
@@ -198,15 +195,23 @@ class DSession(object):
         )
         if maximum_reached:
             if self._max_worker_restart == 0:
-                msg = "Worker restarting disabled"
+                msg = "worker {} crashed and worker restarting disabled".format(
+                    node.gateway.id
+                )
             else:
-                msg = "Maximum crashed workers reached: %d" % self._max_worker_restart
-            self.report_line(msg)
+                msg = "maximum crashed workers reached: %d" % self._max_worker_restart
+            self._summary_report = msg
+            self.report_line("\n" + msg)
+            self.triggershutdown()
         else:
-            self.report_line("Replacing crashed worker %s" % node.gateway.id)
+            self.report_line("\nreplacing crashed worker %s" % node.gateway.id)
             self._clone_node(node)
         self._active_nodes.remove(node)
 
+    def pytest_terminal_summary(self, terminalreporter):
+        if self.config.option.verbose >= 0 and self._summary_report:
+            terminalreporter.write_sep("=", "xdist: {}".format(self._summary_report))
+
     def worker_collectionfinish(self, node, ids):
         """worker has finished test collection.
 
@@ -229,9 +234,10 @@ class DSession(object):
             if self.terminal and not self.sched.has_pending:
                 self.trdist.ensure_show_status()
                 self.terminal.write_line("")
-                self.terminal.write_line(
-                    "scheduling tests via %s" % (self.sched.__class__.__name__)
-                )
+                if self.config.option.verbose > 0:
+                    self.terminal.write_line(
+                        "scheduling tests via %s" % (self.sched.__class__.__name__)
+                    )
             self.sched.schedule()
 
     def worker_logstart(self, node, nodeid, location):
@@ -259,10 +265,10 @@ class DSession(object):
     def worker_collectreport(self, node, rep):
         """Emitted when a node calls the pytest_collectreport hook.
 
-        Because we only need the report when there's a failure, as optimization
-        we only expect to receive failed reports from workers (#330).
+        Because we only need the report when there's a failure/skip, as optimization
+        we only expect to receive failed/skipped reports from workers (#330).
         """
-        assert rep.failed
+        assert not rep.passed
         self._failed_worker_collectreport(node, rep)
 
     def worker_logwarning(self, message, code, nodeid, fslocation):
@@ -270,6 +276,18 @@ class DSession(object):
         kwargs = dict(message=message, code=code, nodeid=nodeid, fslocation=fslocation)
         self.config.hook.pytest_logwarning.call_historic(kwargs=kwargs)
 
+    def worker_warning_captured(self, warning_message, when, item):
+        """Emitted when a node calls the pytest_warning_captured hook (deprecated in 6.0)."""
+        kwargs = dict(warning_message=warning_message, when=when, item=item)
+        self.config.hook.pytest_warning_captured.call_historic(kwargs=kwargs)
+
+    def worker_warning_recorded(self, warning_message, when, nodeid, location):
+        """Emitted when a node calls the pytest_warning_recorded hook."""
+        kwargs = dict(
+            warning_message=warning_message, when=when, nodeid=nodeid, location=location
+        )
+        self.config.hook.pytest_warning_recorded.call_historic(kwargs=kwargs)
+
     def _clone_node(self, node):
         """Return new node based on an existing one.
 
@@ -310,7 +328,7 @@ class DSession(object):
         # XXX count no of failures and retry N times
         runner = self.config.pluginmanager.getplugin("runner")
         fspath = nodeid.split("::")[0]
-        msg = "Worker %r crashed while running %r" % (worker.gateway.id, nodeid)
+        msg = "worker {!r} crashed while running {!r}".format(worker.gateway.id, nodeid)
         rep = runner.TestReport(
             nodeid, (fspath, None, fspath), (), "failed", msg, "???"
         )
@@ -339,8 +357,13 @@ class TerminalDistReporter(object):
             self.rewrite(self.getstatus())
 
     def getstatus(self):
-        parts = ["%s %s" % (spec.id, self._status[spec.id]) for spec in self._specs]
-        return " / ".join(parts)
+        if self.config.option.verbose >= 0:
+            parts = [
+                "{} {}".format(spec.id, self._status[spec.id]) for spec in self._specs
+            ]
+            return " / ".join(parts)
+        else:
+            return "bringing up nodes..."
 
     def rewrite(self, line, newline=False):
         pline = line + " " * max(self._lastlen - len(line), 0)
@@ -372,19 +395,27 @@ class TerminalDistReporter(object):
     def pytest_testnodeready(self, node):
         if self.config.option.verbose > 0:
             d = node.workerinfo
-            infoline = "[%s] Python %s" % (d["id"], d["version"].replace("\n", " -- "))
+            infoline = "[{}] Python {}".format(
+                d["id"], d["version"].replace("\n", " -- ")
+            )
             self.rewrite(infoline, newline=True)
         self.setstatus(node.gateway.spec, "ok")
 
     def pytest_testnodedown(self, node, error):
         if not error:
             return
-        self.write_line("[%s] node down: %s" % (node.gateway.id, error))
+        self.write_line("[{}] node down: {}".format(node.gateway.id, error))
 
-    # def pytest_xdist_rsyncstart(self, source, gateways):
-    #    targets = ",".join([gw.id for gw in gateways])
-    #    msg = "[%s] rsyncing: %s" %(targets, source)
-    #    self.write_line(msg)
-    # def pytest_xdist_rsyncfinish(self, source, gateways):
-    #    targets = ", ".join(["[%s]" % gw.id for gw in gateways])
-    #    self.write_line("rsyncfinish: %s -> %s" %(source, targets))
+
+def get_default_max_worker_restart(config):
+    """gets the default value of --max-worker-restart option if it is not provided.
+
+    Use a reasonable default to avoid workers from restarting endlessly due to crashing collections (#226).
+    """
+    result = config.option.maxworkerrestart
+    if result is not None:
+        result = int(result)
+    elif config.option.numprocesses:
+        # if --max-worker-restart was not provided, use a reasonable default (#226)
+        result = config.option.numprocesses * 4
+    return result

src/xdist/looponfail.py

@@ -30,9 +30,9 @@ def pytest_addoption(parser):
 def pytest_cmdline_main(config):
 
     if config.getoption("looponfail"):
-        usepdb = config.getoption("usepdb")  # a core option
+        usepdb = config.getoption("usepdb", False)  # a core option
         if usepdb:
-            raise pytest.UsageError("--pdb incompatible with --looponfail.")
+            raise pytest.UsageError("--pdb is incompatible with --looponfail.")
         looponfail_main(config)
         return 2  # looponfail only can get stop with ctrl-C anyway
 
@@ -136,7 +136,7 @@ def repr_pytest_looponfailinfo(failreports, rootdirs):
                 tr.line(report, red=True)
     tr.sep("#", "waiting for changes", bold=True)
     for rootdir in rootdirs:
-        tr.line("### Watching:   %s" % (rootdir,), bold=True)
+        tr.line("### Watching:   {}".format(rootdir), bold=True)
 
 
 def init_worker_session(channel, args, option_dict):

src/xdist/newhooks.py

@@ -30,6 +30,11 @@ def pytest_xdist_rsyncfinish(source, gateways):
     """ called after rsyncing a directory to remote gateways takes place. """
 
 
+@pytest.mark.firstresult
+def pytest_xdist_getremotemodule():
+    """ called when creating remote node"""
+
+
 def pytest_configure_node(node):
     """ configure node information before it gets instantiated. """
 

src/xdist/plugin.py

@@ -1,4 +1,5 @@
 import os
+import uuid
 
 import py
 import pytest
@@ -27,10 +28,14 @@ def auto_detect_cpus():
     return n if n else 1
 
 
+class AutoInt(int):
+    """Mark value as auto-detected."""
+
+
 def parse_numprocesses(s):
     if s == "auto":
-        return auto_detect_cpus()
-    else:
+        return AutoInt(auto_detect_cpus())
+    elif s is not None:
         return int(s)
 
 
@@ -45,7 +50,15 @@ def pytest_addoption(parser):
         type=parse_numprocesses,
         help="shortcut for '--dist=load --tx=NUM*popen', "
         "you can use 'auto' here for auto detection CPUs number on "
-        "host system",
+        "host system and it will be 0 when used with --pdb",
+    )
+    group.addoption(
+        "--maxprocesses",
+        dest="maxprocesses",
+        metavar="maxprocesses",
+        action="store",
+        type=int,
+        help="limit the maximum number of workers to process the tests when using --numprocesses=auto",
     )
     group.addoption(
         "--max-worker-restart",
@@ -110,20 +123,30 @@ def pytest_addoption(parser):
         metavar="GLOB",
         help="add expression for ignores when rsyncing to remote tx nodes.",
     )
-
     group.addoption(
         "--boxed",
         action="store_true",
         help="backward compatibility alias for pytest-forked --forked",
     )
+    group.addoption(
+        "--testrunuid",
+        action="store",
+        help=(
+            "provide an identifier shared amongst all workers as the value of "
+            "the 'testrun_uid' fixture,\n\n,"
+            "if not provided, 'testrun_uid' is filled with a new unique string "
+            "on every test run."
+        ),
+    )
+
     parser.addini(
         "rsyncdirs",
-        "list of (relative) paths to be rsynced for" " remote distributed testing.",
+        "list of (relative) paths to be rsynced for remote distributed testing.",
         type="pathlist",
     )
     parser.addini(
         "rsyncignore",
-        "list of (relative) glob-style paths to be ignored " "for rsyncing.",
+        "list of (relative) glob-style paths to be ignored for rsyncing.",
         type="pathlist",
     )
     parser.addini(
@@ -142,11 +165,7 @@ def pytest_addoption(parser):
 def pytest_addhooks(pluginmanager):
     from xdist import newhooks
 
-    # avoid warnings with pytest-2.8
-    method = getattr(pluginmanager, "add_hookspecs", None)
-    if method is None:
-        method = pluginmanager.addhooks
-    method(newhooks)
+    pluginmanager.add_hookspecs(newhooks)
 
 
 # -------------------------------------------------------------------------
@@ -162,26 +181,33 @@ def pytest_configure(config):
         session = DSession(config)
         config.pluginmanager.register(session, "dsession")
         tr = config.pluginmanager.getplugin("terminalreporter")
-        tr.showfspath = False
+        if tr:
+            tr.showfspath = False
     if config.getoption("boxed"):
         config.option.forked = True
 
 
 @pytest.mark.tryfirst
 def pytest_cmdline_main(config):
+    usepdb = config.getoption("usepdb", False)  # a core option
+    if isinstance(config.option.numprocesses, AutoInt):
+        config.option.numprocesses = 0 if usepdb else int(config.option.numprocesses)
+
     if config.option.numprocesses:
         if config.option.dist == "no":
             config.option.dist = "load"
-        config.option.tx = ["popen"] * config.option.numprocesses
+        numprocesses = config.option.numprocesses
+        if config.option.maxprocesses:
+            numprocesses = min(numprocesses, config.option.maxprocesses)
+        config.option.tx = ["popen"] * numprocesses
     if config.option.distload:
         config.option.dist = "load"
     val = config.getvalue
     if not val("collectonly"):
-        usepdb = config.getoption("usepdb")  # a core option
         if val("dist") != "no":
             if usepdb:
                 raise pytest.UsageError(
-                    "--pdb is incompatible with distributing tests; try using -n0."
+                    "--pdb is incompatible with distributing tests; try using -n0 or -nauto."
                 )  # noqa: E501
 
 
@@ -199,3 +225,12 @@ def worker_id(request):
         return request.config.workerinput["workerid"]
     else:
         return "master"
+
+
+@pytest.fixture(scope="session")
+def testrun_uid(request):
+    """Return the unique id of the current test."""
+    if hasattr(request.config, "workerinput"):
+        return request.config.workerinput["testrunuid"]
+    else:
+        return uuid.uuid4().hex

src/xdist/remote.py

@@ -10,14 +10,19 @@ import sys
 import os
 import time
 
+import py
 import _pytest.hookspec
 import pytest
+from execnet.gateway_base import dumps, DumpError
+
+from _pytest.config import _prepareconfig, Config
 
 
 class WorkerInteractor(object):
     def __init__(self, config, channel):
         self.config = config
         self.workerid = config.workerinput.get("workerid", "?")
+        self.testrunuid = config.workerinput["testrunuid"]
         self.log = py.log.Producer("worker-%s" % self.workerid)
         if not config.option.debug:
             py.log.setconsumer(self.log._keywords, None)
@@ -39,7 +44,8 @@ class WorkerInteractor(object):
 
     @pytest.hookimpl(hookwrapper=True)
     def pytest_sessionfinish(self, exitstatus):
-        self.config.workeroutput["exitstatus"] = exitstatus
+        # in pytest 5.0+, exitstatus is an IntEnum object
+        self.config.workeroutput["exitstatus"] = int(exitstatus)
         yield
         self.sendevent("workerfinished", workeroutput=self.config.workeroutput)
 
@@ -102,67 +108,109 @@ class WorkerInteractor(object):
             self.sendevent("logfinish", nodeid=nodeid, location=location)
 
     def pytest_runtest_logreport(self, report):
-        data = serialize_report(report)
+        data = self.config.hook.pytest_report_to_serializable(
+            config=self.config, report=report
+        )
         data["item_index"] = self.item_index
         data["worker_id"] = self.workerid
+        data["testrun_uid"] = self.testrunuid
         assert self.session.items[self.item_index].nodeid == report.nodeid
         self.sendevent("testreport", data=data)
 
     def pytest_collectreport(self, report):
-        # master only needs reports that failed, as optimization send only them instead (#330)
-        if report.failed:
-            data = serialize_report(report)
+        # send only reports that have not passed to master as optimization (#330)
+        if not report.passed:
+            data = self.config.hook.pytest_report_to_serializable(
+                config=self.config, report=report
+            )
             self.sendevent("collectreport", data=data)
 
-    def pytest_logwarning(self, message, code, nodeid, fslocation):
-        self.sendevent(
-            "logwarning",
-            message=message,
-            code=code,
-            nodeid=nodeid,
-            fslocation=str(fslocation),
-        )
+    # the pytest_logwarning hook was deprecated since pytest 4.0
+    if hasattr(
+        _pytest.hookspec, "pytest_logwarning"
+    ) and not _pytest.hookspec.pytest_logwarning.pytest_spec.get("warn_on_impl"):
+
+        def pytest_logwarning(self, message, code, nodeid, fslocation):
+            self.sendevent(
+                "logwarning",
+                message=message,
+                code=code,
+                nodeid=nodeid,
+                fslocation=str(fslocation),
+            )
+
+    # the pytest_warning_captured hook was introduced in pytest 3.8
+    if hasattr(_pytest.hookspec, "pytest_warning_captured"):
+
+        def pytest_warning_captured(self, warning_message, when, item):
+            self.sendevent(
+                "warning_captured",
+                warning_message_data=serialize_warning_message(warning_message),
+                when=when,
+                # item cannot be serialized and will always be None when used with xdist
+                item=None,
+            )
+
+    # the pytest_warning_recorded hook was introduced in pytest 6.0
+    if hasattr(_pytest.hookspec, "pytest_warning_recorded"):
+
+        def pytest_warning_recorded(self, warning_message, when, nodeid, location):
+            self.sendevent(
+                "warning_recorded",
+                warning_message_data=serialize_warning_message(warning_message),
+                when=when,
+                nodeid=nodeid,
+                location=location,
+            )
 
 
-def serialize_report(rep):
-    def disassembled_report(rep):
-        reprtraceback = rep.longrepr.reprtraceback.__dict__.copy()
-        reprcrash = rep.longrepr.reprcrash.__dict__.copy()
-
-        new_entries = []
-        for entry in reprtraceback["reprentries"]:
-            entry_data = {"type": type(entry).__name__, "data": entry.__dict__.copy()}
-            for key, value in entry_data["data"].items():
-                if hasattr(value, "__dict__"):
-                    entry_data["data"][key] = value.__dict__.copy()
-            new_entries.append(entry_data)
-
-        reprtraceback["reprentries"] = new_entries
-
-        return {
-            "reprcrash": reprcrash,
-            "reprtraceback": reprtraceback,
-            "sections": rep.longrepr.sections,
-        }
-
-    import py
-
-    d = rep.__dict__.copy()
-    if hasattr(rep.longrepr, "toterminal"):
-        if hasattr(rep.longrepr, "reprtraceback") and hasattr(
-            rep.longrepr, "reprcrash"
-        ):
-            d["longrepr"] = disassembled_report(rep)
+def serialize_warning_message(warning_message):
+    if isinstance(warning_message.message, Warning):
+        message_module = type(warning_message.message).__module__
+        message_class_name = type(warning_message.message).__name__
+        message_str = str(warning_message.message)
+        # check now if we can serialize the warning arguments (#349)
+        # if not, we will just use the exception message on the master node
+        try:
+            dumps(warning_message.message.args)
+        except DumpError:
+            message_args = None
         else:
-            d["longrepr"] = str(rep.longrepr)
+            message_args = warning_message.message.args
     else:
-        d["longrepr"] = rep.longrepr
-    for name in d:
-        if isinstance(d[name], py.path.local):
-            d[name] = str(d[name])
-        elif name == "result":
-            d[name] = None  # for now
-    return d
+        message_str = warning_message.message
+        message_module = None
+        message_class_name = None
+        message_args = None
+    if warning_message.category:
+        category_module = warning_message.category.__module__
+        category_class_name = warning_message.category.__name__
+    else:
+        category_module = None
+        category_class_name = None
+
+    result = {
+        "message_str": message_str,
+        "message_module": message_module,
+        "message_class_name": message_class_name,
+        "message_args": message_args,
+        "category_module": category_module,
+        "category_class_name": category_class_name,
+    }
+    # access private _WARNING_DETAILS because the attributes vary between Python versions
+    for attr_name in warning_message._WARNING_DETAILS:
+        if attr_name in ("message", "category"):
+            continue
+        attr = getattr(warning_message, attr_name)
+        # Check if we can serialize the warning detail, marking `None` otherwise
+        # Note that we need to define the attr (even as `None`) to allow deserializing
+        try:
+            dumps(attr)
+        except DumpError:
+            result[attr_name] = repr(attr)
+        else:
+            result[attr_name] = attr
+    return result
 
 
 def getinfodict():
@@ -179,33 +227,43 @@ def getinfodict():
 
 
 def remote_initconfig(option_dict, args):
-    from _pytest.config import Config
-
     option_dict["plugins"].append("no:terminal")
-    config = Config.fromdictargs(option_dict, args)
+    return Config.fromdictargs(option_dict, args)
+
+
+def setup_config(config, basetemp):
     config.option.looponfail = False
     config.option.usepdb = False
     config.option.dist = "no"
     config.option.distload = False
     config.option.numprocesses = None
-    config.args = args
-    return config
+    config.option.maxprocesses = None
+    config.option.basetemp = basetemp
 
 
 if __name__ == "__channelexec__":
     channel = channel  # noqa
-    workerinput, args, option_dict = channel.receive()
-    importpath = os.getcwd()
-    sys.path.insert(0, importpath)  # XXX only for remote situations
-    os.environ["PYTHONPATH"] = (
-        importpath + os.pathsep + os.environ.get("PYTHONPATH", "")
-    )
+    workerinput, args, option_dict, change_sys_path = channel.receive()
+
+    if change_sys_path:
+        importpath = os.getcwd()
+        sys.path.insert(0, importpath)
+        os.environ["PYTHONPATH"] = (
+            importpath + os.pathsep + os.environ.get("PYTHONPATH", "")
+        )
+
+    os.environ["PYTEST_XDIST_TESTRUNUID"] = workerinput["testrunuid"]
     os.environ["PYTEST_XDIST_WORKER"] = workerinput["workerid"]
     os.environ["PYTEST_XDIST_WORKER_COUNT"] = str(workerinput["workercount"])
-    # os.environ['PYTHONPATH'] = importpath
-    import py
 
-    config = remote_initconfig(option_dict, args)
+    if hasattr(Config, "InvocationParams"):
+        config = _prepareconfig(args, None)
+    else:
+        config = remote_initconfig(option_dict, args)
+        config.args = args
+
+    setup_config(config, option_dict.get("basetemp"))
+    config._parser.prog = os.path.basename(workerinput["mainargv"][0])
     config.workerinput = workerinput
     config.workeroutput = {}
     # TODO: deprecated name, backward compatibility only. Remove it in future

src/xdist/scheduler/__init__.py

@@ -1,4 +1,4 @@
 from xdist.scheduler.each import EachScheduling  # noqa
 from xdist.scheduler.load import LoadScheduling  # noqa
+from xdist.scheduler.loadfile import LoadFileScheduling  # noqa
 from xdist.scheduler.loadscope import LoadScopeScheduling  # noqa
-from xdist.scheduler.filescope import LoadFileScheduling  # noqa

src/xdist/scheduler/each.py

@@ -126,6 +126,7 @@ class EachScheduling(object):
             if not pending:
                 pending[:] = range(len(self.node2collection[node]))
                 node.send_runtest_all()
+                node.shutdown()
             else:
                 node.send_runtest_some(pending)
             self._started.append(node)

src/xdist/scheduler/load.py

@@ -178,6 +178,9 @@ class LoadScheduling(object):
                     return
                 num_send = items_per_node_max - len(node_pending)
                 self._send_tests(node, num_send)
+        else:
+            node.shutdown()
+
         self.log("num items waiting for node:", len(self.pending))
 
     def remove_node(self, node):

src/xdist/scheduler/loadfile.py

@@ -1,4 +1,4 @@
-from . import LoadScopeScheduling
+from .loadscope import LoadScopeScheduling
 from py.log import Producer
 
 

src/xdist/scheduler/loadscope.py

@@ -187,7 +187,7 @@ class LoadScopeScheduling(object):
             break
         else:
             raise RuntimeError(
-                "Unable to identify crashitem on a workload with " "pending items"
+                "Unable to identify crashitem on a workload with pending items"
             )
 
         # Made uncompleted work unit available again
@@ -306,6 +306,7 @@ class LoadScopeScheduling(object):
 
         # Check that more work is available
         if not self.workqueue:
+            node.shutdown()
             return
 
         self.log("Number of units waiting for node:", len(self.workqueue))
@@ -357,12 +358,12 @@ class LoadScopeScheduling(object):
         extra_nodes = len(self.nodes) - len(self.workqueue)
 
         if extra_nodes > 0:
-            self.log("Shuting down {0} nodes".format(extra_nodes))
+            self.log("Shuting down {} nodes".format(extra_nodes))
 
             for _ in range(extra_nodes):
                 unused_node, assigned = self.assigned_work.popitem(last=True)
 
-                self.log("Shuting down unused node {0}".format(unused_node))
+                self.log("Shuting down unused node {}".format(unused_node))
                 unused_node.shutdown()
 
         # Assign initial workload

src/xdist/workermanage.py

@@ -2,7 +2,8 @@ from __future__ import print_function
 import fnmatch
 import os
 import re
-import threading
+import sys
+import uuid
 
 import py
 import pytest
@@ -10,8 +11,6 @@ import execnet
 
 import xdist.remote
 
-from _pytest import runner  # XXX load dynamically
-
 
 def parse_spec_config(config):
     xspeclist = []
@@ -36,8 +35,10 @@ class NodeManager(object):
 
     def __init__(self, config, specs=None, defaultchdir="pyexecnetcache"):
         self.config = config
-        self._nodesready = threading.Event()
         self.trace = self.config.trace.get("nodemanager")
+        self.testrunuid = self.config.getoption("testrunuid")
+        if self.testrunuid is None:
+            self.testrunuid = uuid.uuid4().hex
         self.group = execnet.Group()
         if specs is None:
             specs = self._getxspecs()
@@ -62,10 +63,7 @@ class NodeManager(object):
     def setup_nodes(self, putevent):
         self.config.hook.pytest_xdist_setupnodes(config=self.config, specs=self.specs)
         self.trace("setting up nodes")
-        nodes = []
-        for spec in self.specs:
-            nodes.append(self.setup_node(spec, putevent))
-        return nodes
+        return [self.setup_node(spec, putevent) for spec in self.specs]
 
     def setup_node(self, spec, putevent):
         gw = self.group.makegateway(spec)
@@ -104,7 +102,7 @@ class NodeManager(object):
         for root in candidates:
             root = py.path.local(root).realpath()
             if not root.check():
-                raise pytest.UsageError("rsyncdir doesn't exist: %r" % (root,))
+                raise pytest.UsageError("rsyncdir doesn't exist: {!r}".format(root))
             if root not in roots:
                 roots.append(root)
         return roots
@@ -115,7 +113,10 @@ class NodeManager(object):
         ignores += self.config.option.rsyncignore
         ignores += self.config.getini("rsyncignore")
 
-        return {"ignores": ignores, "verbose": self.config.option.verbose}
+        return {
+            "ignores": ignores,
+            "verbose": getattr(self.config.option, "verbose", False),
+        }
 
     def rsync(self, gateway, source, notify=None, verbose=False, ignores=None):
         """Perform rsync to remote hosts for node."""
@@ -154,11 +155,10 @@ class HostRSync(execnet.RSync):
 
     def __init__(self, sourcedir, *args, **kwargs):
         self._synced = {}
-        self._ignores = []
         ignores = kwargs.pop("ignores", None) or []
-        for x in ignores:
-            x = getattr(x, "strpath", x)
-            self._ignores.append(re.compile(fnmatch.translate(x)))
+        self._ignores = [
+            re.compile(fnmatch.translate(getattr(x, "strpath", x))) for x in ignores
+        ]
         super(HostRSync, self).__init__(sourcedir=sourcedir, **kwargs)
 
     def filter(self, path):
@@ -179,7 +179,7 @@ class HostRSync(execnet.RSync):
         if self._verbose:
             path = os.path.basename(self._sourcedir) + "/" + modified_rel_path
             remotepath = gateway.spec.chdir
-            print("%s:%s <= %s" % (gateway.spec, remotepath, path))
+            print("{}:{} <= {}".format(gateway.spec, remotepath, path))
 
 
 def make_reltoroot(roots, args):
@@ -189,13 +189,16 @@ def make_reltoroot(roots, args):
     for arg in args:
         parts = arg.split(splitcode)
         fspath = py.path.local(parts[0])
+        if not fspath.exists():
+            result.append(arg)
+            continue
         for root in roots:
             x = fspath.relto(root)
             if x or fspath == root:
                 parts[0] = root.basename + "/" + x
                 break
         else:
-            raise ValueError("arg %s not relative to an rsync root" % (arg,))
+            raise ValueError("arg {} not relative to an rsync root".format(arg))
         result.append(splitcode.join(parts))
     return result
 
@@ -203,7 +206,13 @@ def make_reltoroot(roots, args):
 class WorkerController(object):
     ENDMARK = -1
 
+    class RemoteHook:
+        @pytest.mark.trylast
+        def pytest_xdist_getremotemodule(self):
+            return xdist.remote
+
     def __init__(self, nodemanager, gateway, config, putevent):
+        config.pluginmanager.register(self.RemoteHook())
         self.nodemanager = nodemanager
         self.putevent = putevent
         self.gateway = gateway
@@ -213,6 +222,8 @@ class WorkerController(object):
             "workercount": len(nodemanager.specs),
             "slaveid": gateway.id,
             "slavecount": len(nodemanager.specs),
+            "testrunuid": nodemanager.testrunuid,
+            "mainargv": sys.argv,
         }
         # TODO: deprecated name, backward compatibility only. Remove it in future
         self.slaveinput = self.workerinput
@@ -223,7 +234,7 @@ class WorkerController(object):
             py.log.setconsumer(self.log._keywords, None)
 
     def __repr__(self):
-        return "<%s %s>" % (self.__class__.__name__, self.gateway.id)
+        return "<{} {}>".format(self.__class__.__name__, self.gateway.id)
 
     @property
     def shutting_down(self):
@@ -232,18 +243,27 @@ class WorkerController(object):
     def setup(self):
         self.log("setting up worker session")
         spec = self.gateway.spec
-        args = self.config.args
+        if hasattr(self.config, "invocation_params"):
+            args = [str(x) for x in self.config.invocation_params.args or ()]
+            option_dict = {}
+        else:
+            args = self.config.args
+            option_dict = vars(self.config.option)
         if not spec.popen or spec.chdir:
             args = make_reltoroot(self.nodemanager.roots, args)
-        option_dict = vars(self.config.option)
         if spec.popen:
             name = "popen-%s" % self.gateway.id
             if hasattr(self.config, "_tmpdirhandler"):
                 basetemp = self.config._tmpdirhandler.getbasetemp()
                 option_dict["basetemp"] = str(basetemp.join(name))
         self.config.hook.pytest_configure_node(node=self)
-        self.channel = self.gateway.remote_exec(xdist.remote)
-        self.channel.send((self.workerinput, args, option_dict))
+
+        remote_module = self.config.hook.pytest_xdist_getremotemodule()
+        self.channel = self.gateway.remote_exec(remote_module)
+        # change sys.path only for remote workers
+        change_sys_path = not self.gateway.spec.popen
+        self.channel.send((self.workerinput, args, option_dict, change_sys_path))
+
         if self.putevent:
             self.channel.setcallback(self.process_from_remote, endmarker=self.ENDMARK)
 
@@ -268,17 +288,17 @@ class WorkerController(object):
         if not self._down:
             try:
                 self.sendcommand("shutdown")
-            except IOError:
+            except (IOError, OSError):
                 pass
             self._shutdown_sent = True
 
     def sendcommand(self, name, **kwargs):
         """ send a named parametrized command to the other side. """
-        self.log("sending command %s(**%s)" % (name, kwargs))
+        self.log("sending command {}(**{})".format(name, kwargs))
         self.channel.send((name, kwargs))
 
     def notify_inproc(self, eventname, **kwargs):
-        self.log("queuing %s(**%s)" % (eventname, kwargs))
+        self.log("queuing {}(**{})".format(eventname, kwargs))
         self.putevent((eventname, kwargs))
 
     def process_from_remote(self, eventcall):  # noqa too complex
@@ -300,7 +320,7 @@ class WorkerController(object):
                 return
             eventname, kwargs = eventcall
             if eventname in ("collectionstart",):
-                self.log("ignoring %s(%s)" % (eventname, kwargs))
+                self.log("ignoring {}({})".format(eventname, kwargs))
             elif eventname == "workerready":
                 self.notify_inproc(eventname, node=self, **kwargs)
             elif eventname == "workerfinished":
@@ -311,7 +331,9 @@ class WorkerController(object):
                 self.notify_inproc(eventname, node=self, **kwargs)
             elif eventname in ("testreport", "collectreport", "teardownreport"):
                 item_index = kwargs.pop("item_index", None)
-                rep = unserialize_report(eventname, kwargs["data"])
+                rep = self.config.hook.pytest_report_from_serializable(
+                    config=self.config, data=kwargs["data"]
+                )
                 if item_index is not None:
                     rep.item_index = item_index
                 self.notify_inproc(eventname, node=self, rep=rep)
@@ -327,97 +349,83 @@ class WorkerController(object):
                     nodeid=kwargs["nodeid"],
                     fslocation=kwargs["nodeid"],
                 )
+            elif eventname == "warning_captured":
+                warning_message = unserialize_warning_message(
+                    kwargs["warning_message_data"]
+                )
+                self.notify_inproc(
+                    eventname,
+                    warning_message=warning_message,
+                    when=kwargs["when"],
+                    item=kwargs["item"],
+                )
+            elif eventname == "warning_recorded":
+                warning_message = unserialize_warning_message(
+                    kwargs["warning_message_data"]
+                )
+                self.notify_inproc(
+                    eventname,
+                    warning_message=warning_message,
+                    when=kwargs["when"],
+                    nodeid=kwargs["nodeid"],
+                    location=kwargs["location"],
+                )
             else:
-                raise ValueError("unknown event: %s" % (eventname,))
+                raise ValueError("unknown event: {}".format(eventname))
         except KeyboardInterrupt:
             # should not land in receiver-thread
             raise
         except:  # noqa
             from _pytest._code import ExceptionInfo
 
-            excinfo = ExceptionInfo()
+            # ExceptionInfo API changed in pytest 4.1
+            if hasattr(ExceptionInfo, "from_current"):
+                excinfo = ExceptionInfo.from_current()
+            else:
+                excinfo = ExceptionInfo()
             print("!" * 20, excinfo)
             self.config.notify_exception(excinfo)
             self.shutdown()
             self.notify_inproc("errordown", node=self, error=excinfo)
 
 
-def unserialize_report(name, reportdict):
-    def assembled_report(reportdict):
-        from _pytest._code.code import (
-            ReprEntry,
-            ReprEntryNative,
-            ReprExceptionInfo,
-            ReprFileLocation,
-            ReprFuncArgs,
-            ReprLocals,
-            ReprTraceback,
-        )
+def unserialize_warning_message(data):
+    import warnings
+    import importlib
 
-        if reportdict["longrepr"]:
-            if (
-                "reprcrash" in reportdict["longrepr"]
-                and "reprtraceback" in reportdict["longrepr"]
-            ):
+    if data["message_module"]:
+        mod = importlib.import_module(data["message_module"])
+        cls = getattr(mod, data["message_class_name"])
+        message = None
+        if data["message_args"] is not None:
+            try:
+                message = cls(*data["message_args"])
+            except TypeError:
+                pass
+        if message is None:
+            # could not recreate the original warning instance;
+            # create a generic Warning instance with the original
+            # message at least
+            message_text = "{mod}.{cls}: {msg}".format(
+                mod=data["message_module"],
+                cls=data["message_class_name"],
+                msg=data["message_str"],
+            )
+            message = Warning(message_text)
+    else:
+        message = data["message_str"]
 
-                reprtraceback = reportdict["longrepr"]["reprtraceback"]
-                reprcrash = reportdict["longrepr"]["reprcrash"]
+    if data["category_module"]:
+        mod = importlib.import_module(data["category_module"])
+        category = getattr(mod, data["category_class_name"])
+    else:
+        category = None
 
-                unserialized_entries = []
-                reprentry = None
-                for entry_data in reprtraceback["reprentries"]:
-                    data = entry_data["data"]
-                    entry_type = entry_data["type"]
-                    if entry_type == "ReprEntry":
-                        reprfuncargs = None
-                        reprfileloc = None
-                        reprlocals = None
-                        if data["reprfuncargs"]:
-                            reprfuncargs = ReprFuncArgs(**data["reprfuncargs"])
-                        if data["reprfileloc"]:
-                            reprfileloc = ReprFileLocation(**data["reprfileloc"])
-                        if data["reprlocals"]:
-                            reprlocals = ReprLocals(data["reprlocals"]["lines"])
+    kwargs = {"message": message, "category": category}
+    # access private _WARNING_DETAILS because the attributes vary between Python versions
+    for attr_name in warnings.WarningMessage._WARNING_DETAILS:
+        if attr_name in ("message", "category"):
+            continue
+        kwargs[attr_name] = data[attr_name]
 
-                        reprentry = ReprEntry(
-                            lines=data["lines"],
-                            reprfuncargs=reprfuncargs,
-                            reprlocals=reprlocals,
-                            filelocrepr=reprfileloc,
-                            style=data["style"],
-                        )
-                    elif entry_type == "ReprEntryNative":
-                        reprentry = ReprEntryNative(data["lines"])
-                    else:
-                        report_unserialization_failure(entry_type, name, reportdict)
-                    unserialized_entries.append(reprentry)
-                reprtraceback["reprentries"] = unserialized_entries
-
-                exception_info = ReprExceptionInfo(
-                    reprtraceback=ReprTraceback(**reprtraceback),
-                    reprcrash=ReprFileLocation(**reprcrash),
-                )
-
-                for section in reportdict["longrepr"]["sections"]:
-                    exception_info.addsection(*section)
-                reportdict["longrepr"] = exception_info
-        return reportdict
-
-    if name == "testreport":
-        return runner.TestReport(**assembled_report(reportdict))
-    elif name == "collectreport":
-        return runner.CollectReport(**assembled_report(reportdict))
-
-
-def report_unserialization_failure(type_name, report_name, reportdict):
-    from pprint import pprint
-
-    url = "https://github.com/pytest-dev/pytest-xdist/issues"
-    stream = py.io.TextIO()
-    pprint("-" * 100, stream=stream)
-    pprint("INTERNALERROR: Unknown entry type returned: %s" % type_name, stream=stream)
-    pprint("report_name: %s" % report_name, stream=stream)
-    pprint(reportdict, stream=stream)
-    pprint("Please report this bug at %s" % url, stream=stream)
-    pprint("-" * 100, stream=stream)
-    assert 0, stream.getvalue()
+    return warnings.WarningMessage(**kwargs)

testing/acceptance_test.py

@@ -1,5 +1,6 @@
 import os
 import re
+import sys
 import textwrap
 
 import py
@@ -114,6 +115,9 @@ class TestDistribution:
         assert result.ret == 2
         result.stdout.fnmatch_lines(["*Interrupted: stopping*1*", "*1 failed*"])
 
+    @pytest.mark.xfail(
+        reason="#527: Python 3.8 failure in pytest where testdir.tmpdir returns an unexpected value"
+    )
     def test_basetemp_in_subprocesses(self, testdir):
         p1 = testdir.makepyfile(
             """
@@ -185,16 +189,47 @@ class TestDistribution:
         )
         assert result.ret == 1
 
-    def test_distribution_rsyncdirs_example(self, testdir):
+    @pytest.mark.xfail(reason="#527: Ignore Python 3.8 failure for the time being")
+    def test_distribution_rsyncdirs_example(self, testdir, monkeypatch):
+        # use a custom plugin that has a custom command-line option to ensure
+        # this is propagated to workers (see #491)
+        testdir.makepyfile(
+            **{
+                "myplugin/src/foobarplugin.py": """
+            from __future__ import print_function
+
+            import os
+            import sys
+            import pytest
+
+            def pytest_addoption(parser):
+                parser.addoption("--foobar", action="store", dest="foobar_opt")
+
+            @pytest.mark.tryfirst
+            def pytest_load_initial_conftests(early_config):
+                opt = early_config.known_args_namespace.foobar_opt
+                print("--foobar=%s active! [%s]" % (opt, os.getpid()), file=sys.stderr)
+            """
+            }
+        )
+        assert (testdir.tmpdir / "myplugin/src/foobarplugin.py").check(file=1)
+        monkeypatch.setenv(
+            "PYTHONPATH", str(testdir.tmpdir / "myplugin/src"), prepend=os.pathsep
+        )
+
         source = testdir.mkdir("source")
         dest = testdir.mkdir("dest")
         subdir = source.mkdir("example_pkg")
         subdir.ensure("__init__.py")
         p = subdir.join("test_one.py")
         p.write("def test_5():\n  assert not __file__.startswith(%r)" % str(p))
-        result = testdir.runpytest(
+        result = testdir.runpytest_subprocess(
             "-v",
             "-d",
+            "-s",
+            "-pfoobarplugin",
+            "--foobar=123",
+            "--dist=load",
             "--rsyncdir=%(subdir)s" % locals(),
             "--tx=popen//chdir=%(dest)s" % locals(),
             p,
@@ -208,6 +243,7 @@ class TestDistribution:
                 "*1 passed*",
             ]
         )
+        result.stderr.fnmatch_lines(["--foobar=123 active! *"])
         assert dest.join(subdir.basename).check(dir=1)
 
     def test_backward_compatibility_worker_terminology(self, testdir):
@@ -358,6 +394,30 @@ class TestDistEach:
 
 
 class TestTerminalReporting:
+    @pytest.mark.parametrize("verbosity", ["", "-q", "-v"])
+    def test_output_verbosity(self, testdir, verbosity):
+        testdir.makepyfile(
+            """
+            def test_ok():
+                pass
+        """
+        )
+        args = ["-n1"]
+        if verbosity:
+            args.append(verbosity)
+        result = testdir.runpytest(*args)
+        out = result.stdout.str()
+        if verbosity == "-v":
+            assert "scheduling tests" in out
+            assert "gw" in out
+        elif verbosity == "-q":
+            assert "scheduling tests" not in out
+            assert "gw" not in out
+            assert "bringing up nodes..." in out
+        else:
+            assert "scheduling tests" not in out
+            assert "gw" in out
+
     def test_pass_skip_fail(self, testdir):
         testdir.makepyfile(
             """
@@ -400,33 +460,6 @@ class TestTerminalReporting:
             ]
         )
 
-    @pytest.mark.parametrize("n", ["-n0", "-n1"])
-    @pytest.mark.parametrize("warn_type", ["pytest", "builtin"])
-    def test_logwarning(self, testdir, n, warn_type):
-        from pkg_resources import parse_version
-
-        if parse_version(pytest.__version__) < parse_version("3.1"):
-            pytest.skip("pytest warnings requires >= 3.1")
-
-        if warn_type == "builtin":
-            warn_code = """warnings.warn(UserWarning('this is a warning'))"""
-        elif warn_type == "pytest":
-            warn_code = """request.config.warn('', 'this is a warning',
-                           fslocation=py.path.local())"""
-        else:
-            assert False
-        testdir.makepyfile(
-            """
-            import warnings, py
-            def test_func(request):
-                {warn_code}
-        """.format(
-                warn_code=warn_code
-            )
-        )
-        result = testdir.runpytest(n)
-        result.stdout.fnmatch_lines(["*this is a warning*", "*1 passed, 1 warnings*"])
-
     def test_logfinish_hook(self, testdir):
         """Ensure the pytest_runtest_logfinish hook is being properly handled"""
         from _pytest import hookspec
@@ -492,9 +525,8 @@ def test_session_hooks(testdir):
                 name = "worker"
             else:
                 name = "master"
-            f = open(name, "w")
-            f.write("xy")
-            f.close()
+            with open(name, "w") as f:
+                f.write("xy")
             # let's fail on the worker
             if name == "worker":
                 raise ValueError(42)
@@ -544,16 +576,15 @@ def test_session_testscollected(testdir):
     assert collected_file.read() == "collected = 3"
 
 
-def test_funcarg_teardown_failure(testdir):
+def test_fixture_teardown_failure(testdir):
     p = testdir.makepyfile(
         """
         import pytest
-        @pytest.fixture
+        @pytest.fixture(scope="module")
         def myarg(request):
-            def teardown(val):
-                raise ValueError(val)
-            return request.cached_setup(setup=lambda: 42, teardown=teardown,
-                scope="module")
+            yield 42
+            raise ValueError(42)
+
         def test_hello(myarg):
             pass
     """
@@ -563,6 +594,30 @@ def test_funcarg_teardown_failure(testdir):
     assert result.ret
 
 
+def test_config_initialization(testdir, pytestconfig):
+    """Ensure workers and master are initialized consistently. Integration test for #445"""
+    if not hasattr(pytestconfig, "invocation_params"):
+        pytest.skip(
+            "requires pytest >=5.1 (config has no attribute 'invocation_params')"
+        )
+    testdir.makepyfile(
+        **{
+            "dir_a/test_foo.py": """
+                def test_1(): pass
+        """
+        }
+    )
+    testdir.makefile(
+        ".ini",
+        myconfig="""
+        [pytest]
+        testpaths=dir_a
+    """,
+    )
+    result = testdir.runpytest("-n2", "-c", "myconfig.ini", "-v")
+    result.stdout.fnmatch_lines(["dir_a/test_foo.py::test_1*"])
+
+
 @pytest.mark.parametrize("when", ["setup", "call", "teardown"])
 def test_crashing_item(testdir, when):
     """Ensure crashing item is correctly reported during all testing stages"""
@@ -639,6 +694,11 @@ def test_skipping(testdir):
 
 
 def test_issue34_pluginloading_in_subprocess(testdir):
+    import _pytest.hookspec
+
+    if not hasattr(_pytest.hookspec, "pytest_namespace"):
+        pytest.skip("this pytest version no longer supports pytest_namespace()")
+
     testdir.tmpdir.join("plugin123.py").write(
         textwrap.dedent(
             """
@@ -734,6 +794,108 @@ def test_sub_plugins_disabled(testdir, plugin):
     result.stdout.fnmatch_lines("*1 passed*")
 
 
+class TestWarnings:
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    @pytest.mark.parametrize("warn_type", ["pytest", "builtin"])
+    def test_warnings(self, testdir, n, request, warn_type):
+        if warn_type == "builtin":
+            warn_code = """warnings.warn(UserWarning('this is a warning'))"""
+        elif warn_type == "pytest":
+            if not hasattr(request.config, "warn"):
+                pytest.skip("config.warn has been removed in pytest 4.1")
+            warn_code = """request.config.warn('', 'this is a warning',
+                           fslocation=py.path.local())"""
+        else:
+            assert False
+        testdir.makepyfile(
+            """
+            import warnings, py, pytest
+
+            @pytest.mark.filterwarnings('ignore:config.warn has been deprecated')
+            def test_func(request):
+                {warn_code}
+        """.format(
+                warn_code=warn_code
+            )
+        )
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*this is a warning*", "*1 passed, 1 warning*"])
+
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    def test_custom_subclass(self, testdir, n):
+        """Check that warning subclasses that don't honor the args attribute don't break
+        pytest-xdist (#344)
+        """
+        testdir.makepyfile(
+            """
+            import warnings, py, pytest
+
+            class MyWarning(UserWarning):
+
+                def __init__(self, p1, p2):
+                    self.p1 = p1
+                    self.p2 = p2
+                    self.args = ()
+
+            def test_func(request):
+                warnings.warn(MyWarning("foo", 1))
+        """
+        )
+        testdir.syspathinsert()
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*MyWarning*", "*1 passed, 1 warning*"])
+
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    def test_unserializable_arguments(self, testdir, n):
+        """Check that warnings with unserializable arguments are handled correctly (#349)."""
+        testdir.makepyfile(
+            """
+            import warnings, pytest
+
+            def test_func(tmpdir):
+                fn = (tmpdir / 'foo.txt').ensure(file=1)
+                with fn.open('r') as f:
+                    warnings.warn(UserWarning("foo", f))
+        """
+        )
+        testdir.syspathinsert()
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*UserWarning*foo.txt*", "*1 passed, 1 warning*"])
+
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    def test_unserializable_warning_details(self, testdir, n):
+        """Check that warnings with unserializable _WARNING_DETAILS are
+        handled correctly (#379).
+        """
+        if sys.version_info[0] < 3:
+            # The issue is only present in Python 3 warnings
+            return
+        testdir.makepyfile(
+            """
+            import warnings, pytest
+            import socket
+            import gc
+            def abuse_socket():
+                s = socket.socket()
+                del s
+
+            # Deliberately provoke a ResourceWarning for an unclosed socket.
+            # The socket itself will end up attached as a value in
+            # _WARNING_DETAIL. We need to test that it is not serialized
+            # (it can't be, so the test will fail if we try to).
+            @pytest.mark.filterwarnings('always')
+            def test_func(tmpdir):
+                abuse_socket()
+                gc.collect()
+        """
+        )
+        testdir.syspathinsert()
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(
+            ["*ResourceWarning*unclosed*", "*1 passed, 1 warning*"]
+        )
+
+
 class TestNodeFailure:
     def test_load_single(self, testdir):
         f = testdir.makepyfile(
@@ -746,8 +908,8 @@ class TestNodeFailure:
         res = testdir.runpytest(f, "-n1")
         res.stdout.fnmatch_lines(
             [
-                "*Replacing crashed worker*",
-                "*Worker*crashed while running*",
+                "replacing crashed worker gw*",
+                "worker*crashed while running*",
                 "*1 failed*1 passed*",
             ]
         )
@@ -765,8 +927,8 @@ class TestNodeFailure:
         res = testdir.runpytest(f, "-n2")
         res.stdout.fnmatch_lines(
             [
-                "*Replacing crashed worker*",
-                "*Worker*crashed while running*",
+                "replacing crashed worker gw*",
+                "worker*crashed while running*",
                 "*1 failed*3 passed*",
             ]
         )
@@ -782,8 +944,8 @@ class TestNodeFailure:
         res = testdir.runpytest(f, "--dist=each", "--tx=popen")
         res.stdout.fnmatch_lines(
             [
-                "*Replacing crashed worker*",
-                "*Worker*crashed while running*",
+                "replacing crashed worker gw*",
+                "worker*crashed while running*",
                 "*1 failed*1 passed*",
             ]
         )
@@ -819,14 +981,35 @@ class TestNodeFailure:
         res = testdir.runpytest(f, "-n4", "--max-worker-restart=1")
         res.stdout.fnmatch_lines(
             [
-                "*Replacing crashed worker*",
-                "*Maximum crashed workers reached: 1*",
-                "*Worker*crashed while running*",
-                "*Worker*crashed while running*",
+                "replacing crashed worker*",
+                "maximum crashed workers reached: 1*",
+                "worker*crashed while running*",
+                "worker*crashed while running*",
                 "*2 failed*2 passed*",
             ]
         )
 
+    def test_max_worker_restart_tests_queued(self, testdir):
+        f = testdir.makepyfile(
+            """
+            import os, pytest
+            @pytest.mark.parametrize('i', range(10))
+            def test(i): os._exit(1)
+        """
+        )
+        res = testdir.runpytest(f, "-n2", "--max-worker-restart=3")
+        res.stdout.fnmatch_lines(
+            [
+                "replacing crashed worker*",
+                "maximum crashed workers reached: 3*",
+                "worker*crashed while running*",
+                "worker*crashed while running*",
+                "* xdist: maximum crashed workers reached: 3 *",
+                "* 4 failed in *",
+            ]
+        )
+        assert "INTERNALERROR" not in res.stdout.str()
+
     def test_max_worker_restart_die(self, testdir):
         f = testdir.makepyfile(
             """
@@ -836,7 +1019,10 @@ class TestNodeFailure:
         )
         res = testdir.runpytest(f, "-n4", "--max-worker-restart=0")
         res.stdout.fnmatch_lines(
-            ["*Unexpectedly no active workers*", "*INTERNALERROR*"]
+            [
+                "* xdist: worker gw* crashed and worker restarting disabled *",
+                "* no tests ran in *",
+            ]
         )
 
     def test_disable_restart(self, testdir):
@@ -851,9 +1037,10 @@ class TestNodeFailure:
         res = testdir.runpytest(f, "-n4", "--max-worker-restart=0")
         res.stdout.fnmatch_lines(
             [
-                "*Worker restarting disabled*",
-                "*Worker*crashed while running*",
-                "*1 failed*2 passed*",
+                "worker gw* crashed and worker restarting disabled",
+                "*worker*crashed while running*",
+                "* xdist: worker gw* crashed and worker restarting disabled *",
+                "* 1 failed, 2 passed in *",
             ]
         )
 
@@ -883,6 +1070,29 @@ def test_worker_id_fixture(testdir, n):
         assert worker_ids == {"gw0", "gw1"}
 
 
+@pytest.mark.parametrize("n", [0, 2])
+def test_testrun_uid_fixture(testdir, n):
+    import glob
+
+    f = testdir.makepyfile(
+        """
+        import pytest
+        @pytest.mark.parametrize("run_num", range(2))
+        def test_testrun_uid1(testrun_uid, run_num):
+            with open("testrun_uid%s.txt" % run_num, "w") as f:
+                f.write(testrun_uid)
+    """
+    )
+    result = testdir.runpytest(f, "-n%d" % n)
+    result.stdout.fnmatch_lines("* 2 passed in *")
+    testrun_uids = set()
+    for fname in glob.glob(str(testdir.tmpdir.join("*.txt"))):
+        with open(fname) as f:
+            testrun_uids.add(f.read().strip())
+    assert len(testrun_uids) == 1
+    assert len(testrun_uids.pop()) == 32
+
+
 @pytest.mark.parametrize("tb", ["auto", "long", "short", "no", "line", "native"])
 def test_error_report_styles(testdir, tb):
     testdir.makepyfile(
@@ -922,6 +1132,22 @@ def test_color_yes_collection_on_non_atty(testdir, request):
     assert "gw0 C / gw1 C" not in result.stdout.str()
 
 
+def test_without_terminal_plugin(testdir, request):
+    """
+    No output when terminal plugin is disabled
+    """
+    testdir.makepyfile(
+        """
+        def test_1():
+            pass
+    """
+    )
+    result = testdir.runpytest("-p", "no:terminal", "-n2")
+    assert result.stdout.str() == ""
+    assert result.stderr.str() == ""
+    assert result.ret == 0
+
+
 def test_internal_error_with_maxfail(testdir):
     """
     Internal error when using --maxfail option (#62, #65).
@@ -1101,6 +1327,56 @@ class TestFileScope:
         assert c1 == c2
 
 
+class TestLocking:
+    _test_content = """
+    class TestClassName%s(object):
+
+        @classmethod
+        def setup_class(cls):
+            FILE_LOCK.acquire()
+
+        @classmethod
+        def teardown_class(cls):
+            FILE_LOCK.release()
+
+        def test_a(self):
+            pass
+
+        def test_b(self):
+            pass
+
+        def test_c(self):
+            pass
+
+    """
+
+    test_file1 = """
+    import filelock
+
+    FILE_LOCK = filelock.FileLock("test.lock")
+
+    """ + (
+        (_test_content * 4) % ("A", "B", "C", "D")
+    )
+
+    @pytest.mark.parametrize("scope", ["each", "load", "loadscope", "loadfile", "no"])
+    def test_single_file(self, testdir, scope):
+        testdir.makepyfile(test_a=self.test_file1)
+        result = testdir.runpytest("-n2", "--dist=%s" % scope, "-v")
+        result.assert_outcomes(passed=(12 if scope != "each" else 12 * 2))
+
+    @pytest.mark.parametrize("scope", ["each", "load", "loadscope", "loadfile", "no"])
+    def test_multi_file(self, testdir, scope):
+        testdir.makepyfile(
+            test_a=self.test_file1,
+            test_b=self.test_file1,
+            test_c=self.test_file1,
+            test_d=self.test_file1,
+        )
+        result = testdir.runpytest("-n2", "--dist=%s" % scope, "-v")
+        result.assert_outcomes(passed=(48 if scope != "each" else 48 * 2))
+
+
 def parse_tests_and_workers_from_output(lines):
     result = []
     for line in lines:

testing/conftest.py

@@ -1,20 +1,19 @@
+import six
 import py
 import pytest
 import execnet
 
-
-@pytest.fixture(scope="session", autouse=True)
-def _ensure_imports():
-    # we import some modules because pytest-2.8's testdir fixture
-    # will unload all modules after each test and this cause
-    # (unknown) problems with execnet.Group()
-    execnet.Group
-    execnet.makegateway
-
-
 pytest_plugins = "pytester"
 
-# rsyncdirs = ['.', '../xdist', py.path.local(execnet.__file__).dirpath()]
+if six.PY2:
+
+    @pytest.fixture(scope="session", autouse=True)
+    def _ensure_imports():
+        # we import some modules because pytest-2.8's testdir fixture
+        # will unload all modules after each test and this cause
+        # (unknown) problems with execnet.Group()
+        execnet.Group
+        execnet.makegateway
 
 
 @pytest.fixture(autouse=True)
@@ -23,12 +22,16 @@ def _divert_atexit(request, monkeypatch):
 
     finalizers = []
 
-    def finish():
-        while finalizers:
-            finalizers.pop()()
+    def fake_register(func, *args, **kwargs):
+        finalizers.append((func, args, kwargs))
 
-    monkeypatch.setattr(atexit, "register", finalizers.append)
-    request.addfinalizer(finish)
+    monkeypatch.setattr(atexit, "register", fake_register)
+
+    yield
+
+    while finalizers:
+        func, args, kwargs = finalizers.pop()
+        func(*args, **kwargs)
 
 
 def pytest_addoption(parser):
@@ -45,14 +48,6 @@ def specssh(request):
     return getspecssh(request.config)
 
 
-@pytest.fixture
-def testdir(testdir):
-    # pytest before 2.8 did not have a runpytest_subprocess
-    if not hasattr(testdir, "runpytest_subprocess"):
-        testdir.runpytest_subprocess = testdir.runpytest
-    return testdir
-
-
 # configuration information for tests
 def getgspecs(config):
     return [execnet.XSpec(spec) for spec in config.getvalueorskip("gspecs")]

testing/test_dsession.py

@@ -1,4 +1,4 @@
-from xdist.dsession import DSession
+from xdist.dsession import DSession, get_default_max_worker_restart
 from xdist.report import report_collection_diff
 from xdist.scheduler import EachScheduling, LoadScheduling
 
@@ -268,6 +268,24 @@ def test_report_collection_diff_equal():
     assert report_collection_diff(from_collection, to_collection, 1, 2) is None
 
 
+def test_default_max_worker_restart():
+    class config:
+        class option:
+            maxworkerrestart = None
+            numprocesses = 0
+
+    assert get_default_max_worker_restart(config) is None
+
+    config.option.numprocesses = 2
+    assert get_default_max_worker_restart(config) == 8
+
+    config.option.maxworkerrestart = "1"
+    assert get_default_max_worker_restart(config) == 1
+
+    config.option.maxworkerrestart = "0"
+    assert get_default_max_worker_restart(config) == 0
+
+
 def test_report_collection_diff_different():
     """Test reporting of different collections."""
     from_collection = ["aaa", "bbb", "ccc", "YYY"]

testing/test_looponfail.py

@@ -1,4 +1,7 @@
 import py
+import pytest
+from pkg_resources import parse_version
+
 from xdist.looponfail import RemoteControl
 from xdist.looponfail import StatRecorder
 
@@ -214,7 +217,11 @@ class TestLooponFailing:
         assert "test_one" not in remotecontrol.failures[0]
         assert "test_two" in remotecontrol.failures[0]
 
-    @py.test.mark.xfail(py.test.__version__ >= "3.1", reason="broken by pytest 3.1+")
+    @pytest.mark.xfail(
+        parse_version(pytest.__version__) >= parse_version("3.1"),
+        reason="broken by pytest 3.1+",
+        strict=True,
+    )
     def test_looponfail_removed_test(self, testdir):
         modcol = testdir.getmodulecol(
             """

testing/test_newhooks.py

@@ -15,7 +15,7 @@ class TestHooks:
 
     def test_runtest_logreport(self, testdir):
         """Test that log reports from pytest_runtest_logreport when running
-        with xdist contain "node", "nodeid" and "worker_id" attributes. (#8)
+        with xdist contain "node", "nodeid", "worker_id", and "testrun_uid" attributes. (#8)
         """
         testdir.makeconftest(
             """
@@ -23,20 +23,24 @@ class TestHooks:
                 if hasattr(report, 'node'):
                     if report.when == "call":
                         workerid = report.node.workerinput['workerid']
+                        testrunuid = report.node.workerinput['testrunuid']
                         if workerid != report.worker_id:
                             print("HOOK: Worker id mismatch: %s %s"
                                    % (workerid, report.worker_id))
+                        elif testrunuid != report.testrun_uid:
+                            print("HOOK: Testrun uid mismatch: %s %s"
+                                   % (testrunuid, report.testrun_uid))
                         else:
-                            print("HOOK: %s %s"
-                                   % (report.nodeid, report.worker_id))
+                            print("HOOK: %s %s %s"
+                                   % (report.nodeid, report.worker_id, report.testrun_uid))
         """
         )
         res = testdir.runpytest("-n1", "-s")
         res.stdout.fnmatch_lines(
             [
-                "*HOOK: test_runtest_logreport.py::test_a gw0*",
-                "*HOOK: test_runtest_logreport.py::test_b gw0*",
-                "*HOOK: test_runtest_logreport.py::test_c gw0*",
+                "*HOOK: test_runtest_logreport.py::test_a gw0 *",
+                "*HOOK: test_runtest_logreport.py::test_b gw0 *",
+                "*HOOK: test_runtest_logreport.py::test_c gw0 *",
                 "*3 passed*",
             ]
         )

testing/test_plugin.py

@@ -25,6 +25,10 @@ def test_dist_options(testdir):
     check_options(config)
     assert config.option.dist == "load"
     assert config.option.tx == ["popen"] * 2
+    config = testdir.parseconfigure("--numprocesses", "3", "--maxprocesses", "2")
+    check_options(config)
+    assert config.option.dist == "load"
+    assert config.option.tx == ["popen"] * 2
     config = testdir.parseconfigure("-d")
     check_options(config)
     assert config.option.dist == "load"
@@ -32,6 +36,7 @@ def test_dist_options(testdir):
 
 def test_auto_detect_cpus(testdir, monkeypatch):
     import os
+    from xdist.plugin import pytest_cmdline_main as check_options
 
     if hasattr(os, "sched_getaffinity"):
         monkeypatch.setattr(os, "sched_getaffinity", lambda _pid: set(range(99)))
@@ -48,6 +53,11 @@ def test_auto_detect_cpus(testdir, monkeypatch):
     config = testdir.parseconfigure("-nauto")
     assert config.getoption("numprocesses") == 99
 
+    config = testdir.parseconfigure("-nauto", "--pdb")
+    check_options(config)
+    assert config.getoption("usepdb")
+    assert config.getoption("numprocesses") == 0
+
     monkeypatch.delattr(os, "sched_getaffinity", raising=False)
     monkeypatch.setenv("TRAVIS", "true")
     config = testdir.parseconfigure("-nauto")
@@ -85,6 +95,18 @@ def test_dsession_with_collect_only(testdir):
     assert not config.pluginmanager.hasplugin("dsession")
 
 
+def test_testrunuid_provided(testdir):
+    config = testdir.parseconfigure("--testrunuid", "test123", "--tx=popen")
+    nm = NodeManager(config)
+    assert nm.testrunuid == "test123"
+
+
+def test_testrunuid_generated(testdir):
+    config = testdir.parseconfigure("--tx=popen")
+    nm = NodeManager(config)
+    assert len(nm.testrunuid) == 32
+
+
 class TestDistOptions:
     def test_getxspecs(self, testdir):
         config = testdir.parseconfigure("--tx=popen", "--tx", "ssh=xyz")

testing/test_remote.py

@@ -1,8 +1,10 @@
 import py
 import pprint
 import pytest
-from xdist.workermanage import WorkerController, unserialize_report
-from xdist.remote import serialize_report
+import sys
+import uuid
+
+from xdist.workermanage import WorkerController
 import execnet
 import marshal
 
@@ -24,7 +26,7 @@ class EventCall:
         self.name, self.kwargs = eventcall
 
     def __str__(self):
-        return "<EventCall %s(**%s)>" % (self.name, self.kwargs)
+        return "<EventCall {}(**{})>".format(self.name, self.kwargs)
 
 
 class WorkerSetup:
@@ -43,6 +45,7 @@ class WorkerSetup:
         putevent = self.use_callback and self.events.put or None
 
         class DummyMananger:
+            testrunuid = uuid.uuid4().hex
             specs = [0, 1]
 
         self.slp = WorkerController(DummyMananger, self.gateway, config, putevent)
@@ -58,7 +61,7 @@ class WorkerSetup:
             ev = EventCall(data)
             if name is None or ev.name == name:
                 return ev
-            print("skipping %s" % (ev,))
+            print("skipping {}".format(ev))
 
     def sendcommand(self, name, **kwargs):
         self.slp.sendcommand(name, **kwargs)
@@ -79,188 +82,17 @@ def test_remoteinitconfig(testdir):
     assert config2.pluginmanager.getplugin("terminal") in (-1, None)
 
 
-class TestReportSerialization:
-    def test_xdist_longrepr_to_str_issue_241(self, testdir):
-        testdir.makepyfile(
-            """
-            import os
-            def test_a(): assert False
-            def test_b(): pass
-        """
-        )
-        testdir.makeconftest(
-            """
-            def pytest_runtest_logreport(report):
-                print(report.longrepr)
-        """
-        )
-        res = testdir.runpytest("-n1", "-s")
-        res.stdout.fnmatch_lines(["*1 failed, 1 passed *"])
-
-    def test_xdist_report_longrepr_reprcrash_130(self, testdir):
-        reprec = testdir.inline_runsource(
-            """
-                    import py
-                    def test_fail(): assert False, 'Expected Message'
-                """
-        )
-        reports = reprec.getreports("pytest_runtest_logreport")
-        assert len(reports) == 3
-        rep = reports[1]
-        added_section = ("Failure Metadata", str("metadata metadata"), "*")
-        rep.longrepr.sections.append(added_section)
-        d = serialize_report(rep)
-        check_marshallable(d)
-        a = unserialize_report("testreport", d)
-        # Check assembled == rep
-        assert a.__dict__.keys() == rep.__dict__.keys()
-        for key in rep.__dict__.keys():
-            if key != "longrepr":
-                assert getattr(a, key) == getattr(rep, key)
-        assert rep.longrepr.reprcrash.lineno == a.longrepr.reprcrash.lineno
-        assert rep.longrepr.reprcrash.message == a.longrepr.reprcrash.message
-        assert rep.longrepr.reprcrash.path == a.longrepr.reprcrash.path
-        assert rep.longrepr.reprtraceback.entrysep == a.longrepr.reprtraceback.entrysep
-        assert (
-            rep.longrepr.reprtraceback.extraline == a.longrepr.reprtraceback.extraline
-        )
-        assert rep.longrepr.reprtraceback.style == a.longrepr.reprtraceback.style
-        assert rep.longrepr.sections == a.longrepr.sections
-        # Missing section attribute PR171
-        assert added_section in a.longrepr.sections
-
-    def test_reprentries_serialization_170(self, testdir):
-        from _pytest._code.code import ReprEntry
-
-        reprec = testdir.inline_runsource(
-            """
-                            def test_repr_entry():
-                                x = 0
-                                assert x
-                        """,
-            "--showlocals",
-        )
-        reports = reprec.getreports("pytest_runtest_logreport")
-        assert len(reports) == 3
-        rep = reports[1]
-        d = serialize_report(rep)
-        a = unserialize_report("testreport", d)
-
-        rep_entries = rep.longrepr.reprtraceback.reprentries
-        a_entries = a.longrepr.reprtraceback.reprentries
-        for i in range(len(a_entries)):
-            assert isinstance(rep_entries[i], ReprEntry)
-            assert rep_entries[i].lines == a_entries[i].lines
-            assert rep_entries[i].localssep == a_entries[i].localssep
-            assert rep_entries[i].reprfileloc.lineno == a_entries[i].reprfileloc.lineno
-            assert (
-                rep_entries[i].reprfileloc.message == a_entries[i].reprfileloc.message
-            )
-            assert rep_entries[i].reprfileloc.path == a_entries[i].reprfileloc.path
-            assert rep_entries[i].reprfuncargs.args == a_entries[i].reprfuncargs.args
-            assert rep_entries[i].reprlocals.lines == a_entries[i].reprlocals.lines
-            assert rep_entries[i].style == a_entries[i].style
-
-    def test_reprentries_serialization_196(self, testdir):
-        from _pytest._code.code import ReprEntryNative
-
-        reprec = testdir.inline_runsource(
-            """
-                            def test_repr_entry_native():
-                                x = 0
-                                assert x
-                        """,
-            "--tb=native",
-        )
-        reports = reprec.getreports("pytest_runtest_logreport")
-        assert len(reports) == 3
-        rep = reports[1]
-        d = serialize_report(rep)
-        a = unserialize_report("testreport", d)
-
-        rep_entries = rep.longrepr.reprtraceback.reprentries
-        a_entries = a.longrepr.reprtraceback.reprentries
-        for i in range(len(a_entries)):
-            assert isinstance(rep_entries[i], ReprEntryNative)
-            assert rep_entries[i].lines == a_entries[i].lines
-
-    def test_itemreport_outcomes(self, testdir):
-        reprec = testdir.inline_runsource(
-            """
-            import py
-            def test_pass(): pass
-            def test_fail(): 0/0
-            @py.test.mark.skipif("True")
-            def test_skip(): pass
-            def test_skip_imperative():
-                py.test.skip("hello")
-            @py.test.mark.xfail("True")
-            def test_xfail(): 0/0
-            def test_xfail_imperative():
-                py.test.xfail("hello")
-        """
-        )
-        reports = reprec.getreports("pytest_runtest_logreport")
-        assert len(reports) == 17  # with setup/teardown "passed" reports
-        for rep in reports:
-            d = serialize_report(rep)
-            check_marshallable(d)
-            newrep = unserialize_report("testreport", d)
-            assert newrep.passed == rep.passed
-            assert newrep.failed == rep.failed
-            assert newrep.skipped == rep.skipped
-            if newrep.skipped and not hasattr(newrep, "wasxfail"):
-                assert len(newrep.longrepr) == 3
-            assert newrep.outcome == rep.outcome
-            assert newrep.when == rep.when
-            assert newrep.keywords == rep.keywords
-            if rep.failed:
-                assert newrep.longreprtext == rep.longreprtext
-
-    def test_collectreport_passed(self, testdir):
-        reprec = testdir.inline_runsource("def test_func(): pass")
-        reports = reprec.getreports("pytest_collectreport")
-        for rep in reports:
-            d = serialize_report(rep)
-            check_marshallable(d)
-            newrep = unserialize_report("collectreport", d)
-            assert newrep.passed == rep.passed
-            assert newrep.failed == rep.failed
-            assert newrep.skipped == rep.skipped
-
-    def test_collectreport_fail(self, testdir):
-        reprec = testdir.inline_runsource("qwe abc")
-        reports = reprec.getreports("pytest_collectreport")
-        assert reports
-        for rep in reports:
-            d = serialize_report(rep)
-            check_marshallable(d)
-            newrep = unserialize_report("collectreport", d)
-            assert newrep.passed == rep.passed
-            assert newrep.failed == rep.failed
-            assert newrep.skipped == rep.skipped
-            if rep.failed:
-                assert newrep.longrepr == str(rep.longrepr)
-
-    def test_extended_report_deserialization(self, testdir):
-        reprec = testdir.inline_runsource("qwe abc")
-        reports = reprec.getreports("pytest_collectreport")
-        assert reports
-        for rep in reports:
-            rep.extra = True
-            d = serialize_report(rep)
-            check_marshallable(d)
-            newrep = unserialize_report("collectreport", d)
-            assert newrep.extra
-            assert newrep.passed == rep.passed
-            assert newrep.failed == rep.failed
-            assert newrep.skipped == rep.skipped
-            if rep.failed:
-                assert newrep.longrepr == str(rep.longrepr)
-
-
 class TestWorkerInteractor:
-    def test_basic_collect_and_runtests(self, worker):
+    @pytest.fixture
+    def unserialize_report(self, pytestconfig):
+        def unserialize(data):
+            return pytestconfig.hook.pytest_report_from_serializable(
+                config=pytestconfig, data=data
+            )
+
+        return unserialize
+
+    def test_basic_collect_and_runtests(self, worker, unserialize_report):
         worker.testdir.makepyfile(
             """
             def test_func():
@@ -285,21 +117,18 @@ class TestWorkerInteractor:
         ev = worker.popevent("testreport")  # setup
         ev = worker.popevent("testreport")
         assert ev.name == "testreport"
-        rep = unserialize_report(ev.name, ev.kwargs["data"])
+        rep = unserialize_report(ev.kwargs["data"])
         assert rep.nodeid.endswith("::test_func")
         assert rep.passed
         assert rep.when == "call"
         ev = worker.popevent("workerfinished")
         assert "workeroutput" in ev.kwargs
 
-    @pytest.mark.skipif(
-        pytest.__version__ >= "3.0", reason="skip at module level illegal in pytest 3.0"
-    )
-    def test_remote_collect_skip(self, worker):
+    def test_remote_collect_skip(self, worker, unserialize_report):
         worker.testdir.makepyfile(
             """
-            import py
-            py.test.skip("hello")
+            import pytest
+            pytest.skip("hello", allow_module_level=True)
         """
         )
         worker.setup()
@@ -307,26 +136,25 @@ class TestWorkerInteractor:
         assert not ev.kwargs
         ev = worker.popevent()
         assert ev.name == "collectreport"
-        ev = worker.popevent()
-        assert ev.name == "collectreport"
-        rep = unserialize_report(ev.name, ev.kwargs["data"])
+        rep = unserialize_report(ev.kwargs["data"])
         assert rep.skipped
+        assert rep.longrepr[2] == "Skipped: hello"
         ev = worker.popevent("collectionfinish")
         assert not ev.kwargs["ids"]
 
-    def test_remote_collect_fail(self, worker):
+    def test_remote_collect_fail(self, worker, unserialize_report):
         worker.testdir.makepyfile("""aasd qwe""")
         worker.setup()
         ev = worker.popevent("collectionstart")
         assert not ev.kwargs
         ev = worker.popevent()
         assert ev.name == "collectreport"
-        rep = unserialize_report(ev.name, ev.kwargs["data"])
+        rep = unserialize_report(ev.kwargs["data"])
         assert rep.failed
         ev = worker.popevent("collectionfinish")
         assert not ev.kwargs["ids"]
 
-    def test_runtests_all(self, worker):
+    def test_runtests_all(self, worker, unserialize_report):
         worker.testdir.makepyfile(
             """
             def test_func(): pass
@@ -348,7 +176,7 @@ class TestWorkerInteractor:
             for i in range(3):  # setup/call/teardown
                 ev = worker.popevent("testreport")
                 assert ev.name == "testreport"
-                rep = unserialize_report(ev.name, ev.kwargs["data"])
+                rep = unserialize_report(ev.kwargs["data"])
                 assert rep.nodeid.endswith(func)
         ev = worker.popevent("workerfinished")
         assert "workeroutput" in ev.kwargs
@@ -394,9 +222,71 @@ def test_remote_env_vars(testdir):
         """
         import os
         def test():
+            assert len(os.environ['PYTEST_XDIST_TESTRUNUID']) == 32
             assert os.environ['PYTEST_XDIST_WORKER'] in ('gw0', 'gw1')
             assert os.environ['PYTEST_XDIST_WORKER_COUNT'] == '2'
     """
     )
     result = testdir.runpytest("-n2", "--max-worker-restart=0")
     assert result.ret == 0
+
+
+def test_remote_inner_argv(testdir):
+    """Test/document the behavior due to execnet using `python -c`."""
+    testdir.makepyfile(
+        """
+        import sys
+
+        def test_argv():
+            assert sys.argv == ["-c"]
+        """
+    )
+    result = testdir.runpytest("-n1")
+    assert result.ret == 0
+
+
+def test_remote_mainargv(testdir):
+    outer_argv = sys.argv
+
+    testdir.makepyfile(
+        """
+        def test_mainargv(request):
+            assert request.config.workerinput["mainargv"] == {!r}
+        """.format(
+            outer_argv
+        )
+    )
+    result = testdir.runpytest("-n1")
+    assert result.ret == 0
+
+
+def test_remote_usage_prog(testdir, request):
+    if not hasattr(request.config._parser, "prog"):
+        pytest.skip("prog not available in config parser")
+    testdir.makeconftest(
+        """
+        import pytest
+
+        config_parser = None
+
+        @pytest.fixture
+        def get_config_parser():
+            return config_parser
+
+        def pytest_configure(config):
+            global config_parser
+            config_parser = config._parser
+    """
+    )
+    testdir.makepyfile(
+        """
+        import sys
+
+        def test(get_config_parser, request):
+            get_config_parser._getparser().error("my_usage_error")
+    """
+    )
+
+    result = testdir.runpytest_subprocess("-n1")
+    assert result.ret == 1
+    result.stdout.fnmatch_lines(["*usage: *", "*error: my_usage_error"])

testing/test_slavemanage.py

@@ -168,7 +168,7 @@ class TestNodeManager:
         # assert nodemanager.config.topdir == source == config.topdir
         nodemanager.makegateways()
         nodemanager.rsync_roots()
-        p, = nodemanager.gwmanager.multi_exec(
+        (p,) = nodemanager.gwmanager.multi_exec(
             "import os ; channel.send(os.getcwd())"
         ).receive_each()
         p = py.path.local(p)
@@ -269,5 +269,5 @@ class TestNodeManager:
         reprec = testdir.inline_run(
             "-d", "--rsyncdir=%s" % testdir.tmpdir, "--tx", specssh, testdir.tmpdir
         )
-        rep, = reprec.getreports("pytest_runtest_logreport")
+        (rep,) = reprec.getreports("pytest_runtest_logreport")
         assert rep.passed

tox.ini

@@ -1,32 +1,16 @@
 [tox]
-# if you change the envlist, please update .travis.yml file as well
 envlist=
   linting
-  py{27,34,35,36}-pytest{30,31,32,33,36}
-  py{27,36}-pytest36-pexpect
-  py{27,36}-pytest{master,features}
-
+  py{27,35,36,37,38}-pytestlatest
+  py38-pytestmaster
 
 [testenv]
-changedir=testing
 passenv = USER USERNAME
+extras = testing
 deps =
-  pycmd
-  # to avoid .eggs
-  setuptools_scm
-  pytest30: pytest~=3.0.5
-  pytest31: pytest~=3.1.0
-  pytest32: pytest~=3.2.0
-  pytest33: pytest~=3.3.0
-  pytest36: pytest~=3.6.0
+  pytestlatest: pytest
   pytestmaster: git+https://github.com/pytest-dev/pytest.git@master
-  pytestfeatures: git+https://github.com/pytest-dev/pytest.git@features
-  pexpect: pexpect
-platform=
-  pexpect: linux|darwin
 commands=
-  # always clean to avoid code unmarshal mismatch on old python/pytest
-  py.cleanup -aq
   pytest {posargs}
 
 [testenv:linting]
@@ -39,7 +23,7 @@ commands = pre-commit run --all-files --show-diff-on-failure
 [testenv:release]
 changedir=
 decription = do a release, required posarg of the version number
-basepython = python3.6
+basepython = python3.7
 skipsdist = True
 usedevelop = True
 passenv = *
@@ -49,7 +33,8 @@ commands =
     towncrier --version {posargs} --yes
 
 [pytest]
-addopts = -rsfxX
+addopts = -ra
+testpaths = testing
 
 [flake8]
 max-line-length = 120