Add global session uuid (fixes #524)

src/xdist/plugin.py

@@ -1,4 +1,5 @@
 import os
+import uuid
 
 import py
 import pytest
@@ -122,12 +123,22 @@ 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.",
@@ -214,3 +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

@@ -22,6 +22,7 @@ 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)
@@ -112,6 +113,7 @@ class WorkerInteractor(object):
         )
         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)
 
@@ -238,6 +240,7 @@ if __name__ == "__channelexec__":
             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"])
 

src/xdist/workermanage.py

@@ -3,6 +3,7 @@ import fnmatch
 import os
 import re
 import sys
+import uuid
 
 import py
 import pytest
@@ -35,6 +36,9 @@ class NodeManager(object):
     def __init__(self, config, specs=None, defaultchdir="pyexecnetcache"):
         self.config = config
         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()
@@ -222,6 +226,7 @@ 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