improvement: show return type annotations in fixtures

changelog/13676.improvement.rst

@@ -0,0 +1 @@
+Added return type annotations in ``fixtures`` and ``fixtures-per-test``.

src/_pytest/fixtures.py

@@ -1915,6 +1915,9 @@ def write_fixture(fixture_def: FixtureDef[object]) -> None:
             return
         prettypath = _pretty_fixture_path(invocation_dir, fixture_def.func)
         tw.write(f"{argname}", green=True)
+        ret_annotation = get_return_annotation(fixture_def.func)
+        if ret_annotation:
+            tw.write(f" -> {ret_annotation}", cyan=True)
         tw.write(f" -- {prettypath}", yellow=True)
         tw.write("\n")
         fixture_doc = inspect.getdoc(fixture_def.func)
@@ -1999,6 +2002,9 @@ def _showfixtures_main(config: Config, session: Session) -> None:
         if verbose <= 0 and argname.startswith("_"):
             continue
         tw.write(f"{argname}", green=True)
+        ret_annotation = get_return_annotation(fixturedef.func)
+        if ret_annotation:
+            tw.write(f" -> {ret_annotation}", cyan=True)
         if fixturedef.scope != "function":
             tw.write(f" [{fixturedef.scope} scope]", cyan=True)
         tw.write(f" -- {prettypath}", yellow=True)
@@ -2013,6 +2019,17 @@ def _showfixtures_main(config: Config, session: Session) -> None:
         tw.line()
 
 
+def get_return_annotation(fixture_func: Callable[..., Any]) -> str:
+    try:
+        sig = signature(fixture_func)
+        annotation = sig.return_annotation
+        if annotation is not sig.empty and annotation != inspect._empty:
+            return inspect.formatannotation(annotation).replace("'", "")
+    except (ValueError, TypeError):
+        pass
+    return ""
+
+
 def write_docstring(tw: TerminalWriter, doc: str, indent: str = "    ") -> None:
     for line in doc.split("\n"):
         tw.line(indent + line)

testing/python/fixtures.py

@@ -9,6 +9,7 @@
 from _pytest.compat import getfuncargnames
 from _pytest.config import ExitCode
 from _pytest.fixtures import deduplicate_names
+from _pytest.fixtures import get_return_annotation
 from _pytest.fixtures import TopRequest
 from _pytest.monkeypatch import MonkeyPatch
 from _pytest.pytester import get_public_names
@@ -3581,9 +3582,9 @@ def test_show_fixtures(self, pytester: Pytester) -> None:
         result = pytester.runpytest("--fixtures")
         result.stdout.fnmatch_lines(
             [
-                "tmp_path_factory [[]session scope[]] -- .../_pytest/tmpdir.py:*",
+                "tmp_path_factory* [[]session scope[]] -- .../_pytest/tmpdir.py:*",
                 "*for the test session*",
-                "tmp_path -- .../_pytest/tmpdir.py:*",
+                "tmp_path* -- .../_pytest/tmpdir.py:*",
                 "*temporary directory*",
             ]
         )
@@ -3592,9 +3593,9 @@ def test_show_fixtures_verbose(self, pytester: Pytester) -> None:
         result = pytester.runpytest("--fixtures", "-v")
         result.stdout.fnmatch_lines(
             [
-                "tmp_path_factory [[]session scope[]] -- .../_pytest/tmpdir.py:*",
+                "tmp_path_factory* [[]session scope[]] -- .../_pytest/tmpdir.py:*",
                 "*for the test session*",
-                "tmp_path -- .../_pytest/tmpdir.py:*",
+                "tmp_path* -- .../_pytest/tmpdir.py:*",
                 "*temporary directory*",
             ]
         )
@@ -3614,14 +3615,31 @@ def arg1():
         result = pytester.runpytest("--fixtures", p)
         result.stdout.fnmatch_lines(
             """
-            *tmp_path -- *
+            *tmp_path* -- *
             *fixtures defined from*
             *arg1 -- test_show_fixtures_testmodule.py:6*
             *hello world*
         """
         )
         result.stdout.no_fnmatch_line("*arg0*")
 
+    def test_show_fixtures_return_annotation(self, pytester: Pytester) -> None:
+        p = pytester.makepyfile(
+            """
+            import pytest
+            @pytest.fixture
+            def six() -> int:
+                return 6
+        """
+        )
+        result = pytester.runpytest("--fixtures", p)
+        result.stdout.fnmatch_lines(
+            """
+            *fixtures defined from*
+            *six -> int -- test_show_fixtures_return_annotation.py:3*
+        """
+        )
+
     @pytest.mark.parametrize("testmod", [True, False])
     def test_show_fixtures_conftest(self, pytester: Pytester, testmod) -> None:
         pytester.makeconftest(
@@ -5068,3 +5086,27 @@ def test_method(self, /, fix):
     )
     result = pytester.runpytest()
     result.assert_outcomes(passed=1)
+
+
+def test_get_return_annotation() -> None:
+    def six() -> int:
+        return 6
+
+    assert get_return_annotation(six) == "int"
+
+    def two_sixes() -> tuple[int, str]:
+        return (6, "six")
+
+    assert get_return_annotation(two_sixes) == "tuple[int, str]"
+
+    def no_annot():
+        return 6
+
+    assert get_return_annotation(no_annot) == ""
+
+    def none_return() -> None:
+        pass
+
+    assert get_return_annotation(none_return) == "None"
+
+    assert get_return_annotation(range) == ""