Fix mock patchings detection when both mock and unittest.mock are present

_pytest/compat.py

@@ -79,10 +79,11 @@ def num_mock_patch_args(function):
     patchings = getattr(function, "patchings", None)
     if not patchings:
         return 0
-    mock = sys.modules.get("mock", sys.modules.get("unittest.mock", None))
-    if mock is not None:
+    mock_modules = [sys.modules.get("mock"), sys.modules.get("unittest.mock")]
+    if any(mock_modules):
+        sentinels = [m.DEFAULT for m in mock_modules if m is not None]
         return len([p for p in patchings
-                    if not p.attribute_name and p.new is mock.DEFAULT])
+                    if not p.attribute_name and p.new in sentinels])
     return len(patchings)
 
 

changelog/3206.bugfix.rst

@@ -0,0 +1 @@
+Detect arguments injected by ``unittest.mock.patch`` decorator correctly when pypi ``mock.patch`` is installed and imported.

testing/python/integration.py

@@ -147,6 +147,28 @@ def test_hello(inject_me):
         reprec = testdir.inline_run()
         reprec.assertoutcome(passed=1)
 
+    def test_unittest_mock_and_pypi_mock(self, testdir):
+        pytest.importorskip("unittest.mock")
+        pytest.importorskip("mock", "1.0.1")
+        testdir.makepyfile("""
+            import mock
+            import unittest.mock
+            class TestBoth(object):
+                @unittest.mock.patch("os.path.abspath")
+                def test_hello(self, abspath):
+                    import os
+                    os.path.abspath("hello")
+                    abspath.assert_any_call("hello")
+
+                @mock.patch("os.path.abspath")
+                def test_hello_mock(self, abspath):
+                    import os
+                    os.path.abspath("hello")
+                    abspath.assert_any_call("hello")
+        """)
+        reprec = testdir.inline_run()
+        reprec.assertoutcome(passed=2)
+
     def test_mock(self, testdir):
         pytest.importorskip("mock", "1.0.1")
         testdir.makepyfile("""