Merge pull request #12129 from WarrenTheRabbit/exclude-psuedo-fixtures-from-fixtures-per-test-output

improve(fixtures-per-test): exclude pseudo fixtures from output #11295

Author: bluetech

AUTHORS

@@ -495,6 +495,7 @@ Vlad Radziuk
 Vladyslav Rachek
 Volodymyr Kochetkov
 Volodymyr Piskun
+Warren Markham
 Wei Lin
 Wil Cooley
 Will Riley

changelog/11295.improvement.rst

@@ -0,0 +1 @@
+Improved output of ``--fixtures-per-test`` by excluding internal-implementation fixtures generated by ``@pytest.mark.parametrize`` and similar.

src/_pytest/fixtures.py

@@ -1977,6 +1977,36 @@ def _pretty_fixture_path(invocation_dir: Path, func) -> str:
         return bestrelpath(invocation_dir, loc)
 
 
+def _get_fixtures_per_test(test: nodes.Item) -> Iterator[FixtureDef[object]]:
+    """Returns all fixtures used by the test item except for those created by
+    direct parametrization and those requested dynamically with
+    ``request.getfixturevalue``.
+
+    The justification for excluding fixtures created by direct parametrization
+    is that for users, they are internal implementation detail.
+
+    Dynamically requested fixtures are excluded because they are not known
+    statically.
+    """
+    from _pytest.python import DirectParamFixtureDef
+
+    # Custom Items may not have _fixtureinfo attribute.
+    fixture_info: FuncFixtureInfo | None = getattr(test, "_fixtureinfo", None)
+    if fixture_info is None:
+        return  # pragma: no cover
+
+    # dict key not used in loop but needed for sorting.
+    for argname, fixturedefs in sorted(fixture_info.name2fixturedefs.items()):
+        if not fixturedefs:
+            # Not supposed to be empty, but for safety.
+            continue  # pragma: no cover
+        # Last item is expected to be the one directly used by the test item.
+        fixturedef = fixturedefs[-1]
+        if isinstance(fixturedef, DirectParamFixtureDef):
+            continue
+        yield fixturedef
+
+
 def _show_fixtures_per_test(config: Config, session: Session) -> None:
     import _pytest.config
 
@@ -2009,22 +2039,18 @@ def write_fixture(fixture_def: FixtureDef[object]) -> None:
             tw.line("    no docstring available", red=True)
 
     def write_item(item: nodes.Item) -> None:
-        # Not all items have _fixtureinfo attribute.
-        info: FuncFixtureInfo | None = getattr(item, "_fixtureinfo", None)
-        if info is None or not info.name2fixturedefs:
+        fixturedefs = list(_get_fixtures_per_test(item))
+        if not fixturedefs:
             # This test item does not use any fixtures.
             return
+
         tw.line()
         tw.sep("-", f"fixtures used by {item.name}")
         # TODO: Fix this type ignore.
         tw.sep("-", f"({get_best_relpath(item.function)})")  # type: ignore[attr-defined]
-        # dict key not used in loop but needed for sorting.
-        for _, fixturedefs in sorted(info.name2fixturedefs.items()):
-            assert fixturedefs is not None
-            if not fixturedefs:
-                continue
-            # Last item is expected to be the one used by the test item.
-            write_fixture(fixturedefs[-1])
+
+        for fixturedef in fixturedefs:
+            write_fixture(fixturedef)
 
     for session_item in session.items:
         write_item(session_item)

src/_pytest/python.py

@@ -55,6 +55,7 @@
 from _pytest.fixtures import _resolve_args_directness
 from _pytest.fixtures import FixtureDef
 from _pytest.fixtures import FixtureRequest
+from _pytest.fixtures import FixtureValue
 from _pytest.fixtures import FuncFixtureInfo
 from _pytest.fixtures import get_scope_node
 from _pytest.main import Session
@@ -1095,8 +1096,7 @@ class CallSpec2:
     and stored in item.callspec.
     """
 
-    # arg name -> arg value which will be passed to a fixture or pseudo-fixture
-    # of the same name. (indirect or direct parametrization respectively)
+    # arg name -> arg value which will be passed to a fixture of the same name.
     params: dict[str, object] = dataclasses.field(default_factory=dict)
     # arg name -> arg index.
     indices: dict[str, int] = dataclasses.field(default_factory=dict)
@@ -1153,8 +1153,30 @@ def get_direct_param_fixture_func(request: FixtureRequest) -> Any:
     return request.param
 
 
-# Used for storing pseudo fixturedefs for direct parametrization.
-name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any]]]()
+class DirectParamFixtureDef(FixtureDef[FixtureValue]):
+    """A custom FixtureDef for direct parametrization fixtures.
+
+    Each parameter in direct parametrization is desugared to a parametrized
+    fixture which returns the direct parameterization value as its param.
+    We use this custom type as a "marker" for this type of FixtureDef, but
+    usually behaves like any other FixtureDef.
+    """
+
+    def __init__(self, *, config: Config, argname: str, scope: Scope) -> None:
+        super().__init__(
+            config=config,
+            baseid="",
+            argname=argname,
+            func=get_direct_param_fixture_func,
+            scope=scope,
+            params=None,
+            ids=None,
+            _ispytest=True,
+        )
+
+
+# Used for storing fixturedefs for direct parametrization.
+name2directparamfixturedef_key = StashKey[dict[str, DirectParamFixtureDef[object]]]()
 
 
 @final
@@ -1333,14 +1355,14 @@ def parametrize(
         self._params_directness.update(arg_directness)
 
         # Add direct parametrizations as fixturedefs to arg2fixturedefs by
-        # registering artificial "pseudo" FixtureDef's such that later at test
+        # registering artificial DirectParamFixtureDef's such that later at test
         # setup time we can rely on FixtureDefs to exist for all argnames.
         node = None
-        # For scopes higher than function, a "pseudo" FixtureDef might have
+        # For scopes higher than function, a DirectParamFixtureDef might have
         # already been created for the scope. We thus store and cache the
-        # FixtureDef on the node related to the scope.
+        # DirectParamFixtureDef on the node related to the scope.
         if scope_ is Scope.Function:
-            name2pseudofixturedef = None
+            name2directparamfixturedef = None
         else:
             collector = self.definition.parent
             assert collector is not None
@@ -1357,28 +1379,26 @@ def parametrize(
                     node = collector.session
                 else:
                     assert False, f"Unhandled missing scope: {scope}"
-            default: dict[str, FixtureDef[Any]] = {}
-            name2pseudofixturedef = node.stash.setdefault(
-                name2pseudofixturedef_key, default
+            default: dict[str, DirectParamFixtureDef[object]] = {}
+            name2directparamfixturedef = node.stash.setdefault(
+                name2directparamfixturedef_key, default
             )
         for argname in argnames:
             if arg_directness[argname] == "indirect":
                 continue
-            if name2pseudofixturedef is not None and argname in name2pseudofixturedef:
-                fixturedef = name2pseudofixturedef[argname]
+            if (
+                name2directparamfixturedef is not None
+                and argname in name2directparamfixturedef
+            ):
+                fixturedef = name2directparamfixturedef[argname]
             else:
-                fixturedef = FixtureDef(
+                fixturedef = DirectParamFixtureDef(
                     config=self.config,
-                    baseid="",
                     argname=argname,
-                    func=get_direct_param_fixture_func,
                     scope=scope_,
-                    params=None,
-                    ids=None,
-                    _ispytest=True,
                 )
-                if name2pseudofixturedef is not None:
-                    name2pseudofixturedef[argname] = fixturedef
+                if name2directparamfixturedef is not None:
+                    name2directparamfixturedef[argname] = fixturedef
             self._arg2fixturedefs[argname] = [fixturedef]
 
         # Create the new calls: if we are parametrize() multiple times (by applying the decorator

testing/python/metafunc.py

@@ -801,7 +801,7 @@ def func(x, y):
         metafunc = self.Metafunc(func)
         metafunc.parametrize("x, y", [("a", "b")], indirect=["x"])
         assert metafunc._calls[0].params == dict(x="a", y="b")
-        # Since `y` is a direct parameter, its pseudo-fixture would
+        # Since `y` is a direct parameter, its DirectParamFixtureDef would
         # be registered.
         assert list(metafunc._arg2fixturedefs.keys()) == ["y"]
 

testing/python/show_fixtures_per_test.py

@@ -3,7 +3,7 @@
 from _pytest.pytester import Pytester
 
 
-def test_no_items_should_not_show_output(pytester: Pytester) -> None:
+def test_should_show_no_output_when_zero_items(pytester: Pytester) -> None:
     result = pytester.runpytest("--fixtures-per-test")
     result.stdout.no_fnmatch_line("*fixtures used by*")
     assert result.ret == 0
@@ -254,3 +254,75 @@ def test_arg1(arg1):
             "    Docstring content that extends into a third paragraph.",
         ]
     )
+
+
+def test_should_not_show_direct_param_fixtures(pytester: Pytester) -> None:
+    """A direct-param fixture is a helper fixture created as an implementation
+    detail of direct parametrization.
+
+    These fixtures should not be included in the output because they don't
+    satisfy user expectations for how fixtures are created and used (#11295).
+    """
+    pytester.makepyfile(
+        """
+        import pytest
+
+        @pytest.mark.parametrize("x", [1])
+        def test_pseudo_fixture(x):
+            pass
+        """
+    )
+    result = pytester.runpytest("--fixtures-per-test")
+    result.stdout.no_fnmatch_line("*fixtures used by*")
+    assert result.ret == 0
+
+
+def test_should_show_parametrized_fixtures_used_by_test(pytester: Pytester) -> None:
+    """A fixture with parameters should be included if it was created using
+    the @pytest.fixture decorator, including those that are indirectly
+    parametrized."""
+    pytester.makepyfile(
+        '''
+        import pytest
+
+        @pytest.fixture(params=['a', 'b'])
+        def directly(request):
+            """parametrized fixture"""
+            return request.param
+
+        @pytest.fixture
+        def indirectly(request):
+            """indirectly parametrized fixture"""
+            return request.param
+
+        def test_directly_parametrized_fixture(directly):
+            pass
+
+        @pytest.mark.parametrize("indirectly", ["a", "b"], indirect=True)
+        def test_indirectly_parametrized_fixture(indirectly):
+            pass
+        '''
+    )
+    result = pytester.runpytest("--fixtures-per-test")
+    assert result.ret == 0
+
+    result.stdout.fnmatch_lines(
+        [
+            "*fixtures used by test_directly_parametrized_fixture*",
+            "*(test_should_show_parametrized_fixtures_used_by_test.py:14)*",
+            "directly -- test_should_show_parametrized_fixtures_used_by_test.py:4",
+            "    parametrized fixture",
+            "*fixtures used by test_directly_parametrized_fixture*",
+            "*(test_should_show_parametrized_fixtures_used_by_test.py:14)*",
+            "directly -- test_should_show_parametrized_fixtures_used_by_test.py:4",
+            "    parametrized fixture",
+            "*fixtures used by test_indirectly_parametrized_fixture*",
+            "*(test_should_show_parametrized_fixtures_used_by_test.py:17)*",
+            "indirectly -- test_should_show_parametrized_fixtures_used_by_test.py:9",
+            "    indirectly parametrized fixture",
+            "*fixtures used by test_indirectly_parametrized_fixture*",
+            "*(test_should_show_parametrized_fixtures_used_by_test.py:17)*",
+            "indirectly -- test_should_show_parametrized_fixtures_used_by_test.py:9",
+            "    indirectly parametrized fixture",
+        ]
+    )