Merge pull request #4860 from nicoddemus/getfixturevalue-cleanup-1895

getfixturevalue does not correctly declare dependency with the calling fixture

Author: nicoddemus

changelog/1895.bugfix.rst

@@ -0,0 +1,2 @@
+Fix bug where fixtures requested dynamically via ``request.getfixturevalue()`` might be teardown
+before the requesting fixture.

src/_pytest/fixtures.py

@@ -585,11 +585,13 @@ def _compute_fixture_value(self, fixturedef):
             # call the fixture function
             fixturedef.execute(request=subrequest)
         finally:
-            # if fixture function failed it might have registered finalizers
-            self.session._setupstate.addfinalizer(
-                functools.partial(fixturedef.finish, request=subrequest),
-                subrequest.node,
-            )
+            self._schedule_finalizers(fixturedef, subrequest)
+
+    def _schedule_finalizers(self, fixturedef, subrequest):
+        # if fixture function failed it might have registered finalizers
+        self.session._setupstate.addfinalizer(
+            functools.partial(fixturedef.finish, request=subrequest), subrequest.node
+        )
 
     def _check_scope(self, argname, invoking_scope, requested_scope):
         if argname == "request":
@@ -659,6 +661,16 @@ def __repr__(self):
     def addfinalizer(self, finalizer):
         self._fixturedef.addfinalizer(finalizer)
 
+    def _schedule_finalizers(self, fixturedef, subrequest):
+        # if the executing fixturedef was not explicitly requested in the argument list (via
+        # getfixturevalue inside the fixture call) then ensure this fixture def will be finished
+        # first
+        if fixturedef.argname not in self.funcargnames:
+            fixturedef.addfinalizer(
+                functools.partial(self._fixturedef.finish, request=self)
+            )
+        super(SubRequest, self)._schedule_finalizers(fixturedef, subrequest)
+
 
 scopes = "session package module class function".split()
 scopenum_function = scopes.index("function")

testing/python/fixture.py renamed to testing/python/fixtures.py

@@ -562,6 +562,44 @@ def test_func(something):
         reprec = testdir.inline_run()
         reprec.assertoutcome(passed=1)
 
+    def test_getfixturevalue_teardown(self, testdir):
+        """
+        Issue #1895
+
+        `test_inner` requests `inner` fixture, which in turn requests `resource`
+        using `getfixturevalue`. `test_func` then requests `resource`.
+
+        `resource` is teardown before `inner` because the fixture mechanism won't consider
+        `inner` dependent on `resource` when it is used via `getfixturevalue`: `test_func`
+        will then cause the `resource`'s finalizer to be called first because of this.
+        """
+        testdir.makepyfile(
+            """
+            import pytest
+
+            @pytest.fixture(scope='session')
+            def resource():
+                r = ['value']
+                yield r
+                r.pop()
+
+            @pytest.fixture(scope='session')
+            def inner(request):
+                resource = request.getfixturevalue('resource')
+                assert resource == ['value']
+                yield
+                assert resource == ['value']
+
+            def test_inner(inner):
+                pass
+
+            def test_func(resource):
+                pass
+        """
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("* 2 passed in *")
+
     @pytest.mark.parametrize("getfixmethod", ("getfixturevalue", "getfuncargvalue"))
     def test_getfixturevalue(self, testdir, getfixmethod):
         item = testdir.getitem(