Issue 2836 fixture collection bug

AUTHORS

@@ -164,6 +164,7 @@ Stephan Obermann
 Tareq Alayan
 Ted Xiao
 Thomas Grainger
+Tom Dalton
 Tom Viner
 Trevor Bekolay
 Tyler Goodlet

_pytest/fixtures.py

@@ -1130,7 +1130,40 @@ def getfixturedefs(self, argname, nodeid):
         else:
             return tuple(self._matchfactories(fixturedefs, nodeid))
 
+    @classmethod
+    def _splitnode(cls, nodeid):
+        """Split a nodeid into constituent 'parts'.
+
+        Node IDs are strings, and can be things like:
+            '',
+            'testing/code',
+            'testing/code/test_excinfo.py'
+            'testing/code/test_excinfo.py::TestFormattedExcinfo::()'
+
+        """
+        if nodeid == '':
+            return []
+        sep = py.path.local.sep
+        parts = nodeid.split(sep)
+        last_part = parts[-1]
+        if '::' in last_part:
+            # Replace single last element 'test_foo.py::Bar::()' with multiple elements 'test_foo.py', 'Bar', '()'
+            parts[-1:] = last_part.split("::")
+        return parts
+
+    @classmethod
+    def _ischildnode(cls, baseid, nodeid):
+        """Return True if the nodeid is a child node of the baseid.
+
+        E.g. 'foo/bar::Baz::()' is a child of 'foo', 'foo/bar' and 'foo/bar::Baz', but not of 'foo/blorp'
+        """
+        base_parts = cls._splitnode(baseid)
+        node_parts = cls._splitnode(nodeid)
+        if len(node_parts) < len(base_parts):
+            return False
+        return node_parts[:len(base_parts)] == base_parts
+
     def _matchfactories(self, fixturedefs, nodeid):
         for fixturedef in fixturedefs:
-            if nodeid.startswith(fixturedef.baseid):
+            if self._ischildnode(fixturedef.baseid, nodeid):
                 yield fixturedef

changelog/2836.bug

@@ -0,0 +1,3 @@
+Attempted fix for https://github.com/pytest-dev/pytest/issues/2836
+
+Improves the handling of "nodeid"s to be more aware of path and class separators.

testing/test_collection.py

@@ -2,6 +2,7 @@
 import pytest
 import py
 
+import _pytest._code
 from _pytest.main import Session, EXIT_NOTESTSCOLLECTED, _in_venv
 
 
@@ -830,3 +831,28 @@ def test_continue_on_collection_errors_maxfail(testdir):
         "*Interrupted: stopping after 3 failures*",
         "*1 failed, 2 error*",
     ])
+
+
+def test_fixture_scope_sibling_conftests(testdir):
+    """Regression test case for https://github.com/pytest-dev/pytest/issues/2836"""
+    foo_path = testdir.mkpydir("foo")
+    foo_path.join("conftest.py").write(_pytest._code.Source("""
+        import pytest
+        @pytest.fixture
+        def fix():
+            return 1
+    """))
+    foo_path.join("test_foo.py").write("def test_foo(fix): assert fix == 1")
+
+    # Tests in `food/` should not see the conftest fixture from `foo/`
+    food_path = testdir.mkpydir("food")
+    food_path.join("test_food.py").write("def test_food(fix): assert fix == 1")
+
+    res = testdir.runpytest()
+    assert res.ret == 1
+
+    res.stdout.fnmatch_lines([
+        "*ERROR at setup of test_food*",
+        "E*fixture 'fix' not found",
+        "*1 passed, 1 error*",
+    ])

testing/test_fixtures.py

@@ -0,0 +1,18 @@
+import pytest
+
+from _pytest import fixtures
+
+
+@pytest.mark.parametrize("baseid, nodeid, expected", (
+    ('', '', True),
+    ('', 'foo', True),
+    ('', 'foo/bar', True),
+    ('', 'foo/bar::TestBaz::()', True),
+    ('foo', 'food', False),
+    ('foo/bar::TestBaz::()', 'foo/bar', False),
+    ('foo/bar::TestBaz::()', 'foo/bar::TestBop::()', False),
+    ('foo/bar', 'foo/bar::TestBop::()', True),
+))
+def test_fixturemanager_ischildnode(baseid, nodeid, expected):
+    result = fixtures.FixtureManager._ischildnode(baseid, nodeid)
+    assert result is expected