Merge pull request #49 from nicoddemus/worker-id-fixture

Worker id fixture

CHANGELOG

@@ -1,6 +1,9 @@
-1.14.1.dev
+1.15.0.dev
 ----------
 
+- new ``worker_id`` fixture, returns the id of the worker in a test or fixture.
+  Thanks Jared Hellman for the PR.
+
 
 1.14
 ----

README.rst

@@ -185,6 +185,19 @@ at once.   The specifications strings use the `xspec syntax`_.
 
 .. _`execnet`: http://codespeak.net/execnet
 
+Identifying the worker process during a test
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+If you need to determine the identity of a worker process in
+a test or fixture, you may use the ``worker_id`` fixture to do so::
+
+    @pytest.fixture()
+    def user_account(worker_id):
+        """ use a different account in each xdist worker """
+        return "account_%s" % worker_id
+
+When ``xdist`` is disabled (running with ``-n0`` for example), then
+``worker_id`` will return ``"master"``.
+
 Specifying test exec environments in an ini file
 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 

testing/acceptance_test.py

@@ -620,3 +620,25 @@ class TestNodeFailure:
             "*Slave*crashed while running*",
             "*1 failed*2 passed*",
         ])
+
+
+@pytest.mark.parametrize('n', [0, 2])
+def test_worker_id_fixture(testdir, n):
+    import glob
+    f = testdir.makepyfile("""
+        import pytest
+        @pytest.mark.parametrize("run_num", range(2))
+        def test_worker_id1(worker_id, run_num):
+            with open("worker_id%s.txt" % run_num, "w") as f:
+                f.write(worker_id)
+    """)
+    result = testdir.runpytest(f, "-n%d" % n)
+    result.stdout.fnmatch_lines('* 2 passed in *')
+    worker_ids = set()
+    for fname in glob.glob(str(testdir.tmpdir.join("*.txt"))):
+        with open(fname) as f:
+            worker_ids.add(f.read().strip())
+    if n == 0:
+        assert worker_ids == set(['master'])
+    else:
+        assert worker_ids == set(['gw0', 'gw1'])

xdist/plugin.py

@@ -99,3 +99,15 @@ def pytest_cmdline_main(config):
             if usepdb:
                 raise pytest.UsageError(
                     "--pdb incompatible with distributing tests.")
+
+# -------------------------------------------------------------------------
+# fixtures
+# -------------------------------------------------------------------------
+
+
+@pytest.fixture(scope="session")
+def worker_id(request):
+    if hasattr(request.config, 'slaveinput'):
+        return request.config.slaveinput['slaveid']
+    else:
+        return 'master'