Remove _pytest.compat.is_generator() fixes #12960

changelog/12960.breaking.rst

@@ -0,0 +1,3 @@
+Test functions containing a yield now cause an explicit error. They have not been run since pytest 4.0, and were previously marked as an expected failure and deprecation warning.
+
+See :ref:`the docs <yield tests deprecated>` for more information.

doc/en/deprecations.rst

@@ -374,6 +374,42 @@ an appropriate period of deprecation has passed.
 
 Some breaking changes which could not be deprecated are also listed.
 
+.. _yield tests deprecated:
+
+``yield`` tests
+~~~~~~~~~~~~~~~
+
+.. versionremoved:: 4.0
+
+ ``yield`` tests ``xfail``.
+
+.. versionremoved:: 8.4
+
+ ``yield`` tests raise a collection error.
+
+pytest no longer supports ``yield``-style tests, where a test function actually ``yield`` functions and values
+that are then turned into proper test methods. Example:
+
+.. code-block:: python
+
+ def check(x, y):
+ assert x**x == y
+
+
+ def test_squared():
+ yield check, 2, 4
+ yield check, 3, 9
+
+This would result in two actual test functions being generated.
+
+This form of test function doesn't support fixtures properly, and users should switch to ``pytest.mark.parametrize``:
+
+.. code-block:: python
+
+ @pytest.mark.parametrize("x, y", [(2, 4), (3, 9)])
+ def test_squared(x, y):
+ assert x**x == y
+
 .. _nose-deprecation:
 
 Support for tests written for nose
@@ -1270,36 +1306,6 @@ with the ``name`` parameter:
  return cell()
 
 
-.. _yield tests deprecated:
-
-``yield`` tests
-~~~~~~~~~~~~~~~
-
-.. versionremoved:: 4.0
-
-pytest supported ``yield``-style tests, where a test function actually ``yield`` functions and values
-that are then turned into proper test methods. Example:
-
-.. code-block:: python
-
- def check(x, y):
- assert x**x == y
-
-
- def test_squared():
- yield check, 2, 4
- yield check, 3, 9
-
-This would result into two actual test functions being generated.
-
-This form of test function doesn't support fixtures properly, and users should switch to ``pytest.mark.parametrize``:
-
-.. code-block:: python
-
- @pytest.mark.parametrize("x, y", [(2, 4), (3, 9)])
- def test_squared(x, y):
- assert x**x == y
-
 .. _internal classes accessed through node deprecated:
 
 Internal classes accessed through ``Node``

src/_pytest/compat.py

@@ -43,11 +43,6 @@ class NotSetType(enum.Enum):
 # fmt: on
 
 
-def is_generator(func: object) -> bool:
- genfunc = inspect.isgeneratorfunction(func)
- return genfunc and not iscoroutinefunction(func)
-
-
 def iscoroutinefunction(func: object) -> bool:
  """Return True if func is a coroutine function (a function defined with async
  def syntax, and doesn't contain yield), or a function decorated with

src/_pytest/fixtures.py

@@ -49,7 +49,6 @@
 from _pytest.compat import getfuncargnames
 from _pytest.compat import getimfunc
 from _pytest.compat import getlocation
-from _pytest.compat import is_generator
 from _pytest.compat import NOTSET
 from _pytest.compat import NotSetType
 from _pytest.compat import safe_getattr
@@ -893,7 +892,7 @@ def toterminal(self, tw: TerminalWriter) -> None:
 def call_fixture_func(
  fixturefunc: _FixtureFunc[FixtureValue], request: FixtureRequest, kwargs
 ) -> FixtureValue:
- if is_generator(fixturefunc):
+ if inspect.isgeneratorfunction(fixturefunc):
  fixturefunc = cast(
  Callable[..., Generator[FixtureValue, None, None]], fixturefunc
  )

src/_pytest/python.py

@@ -43,7 +43,6 @@
 from _pytest.compat import get_real_func
 from _pytest.compat import getimfunc
 from _pytest.compat import is_async_function
-from _pytest.compat import is_generator
 from _pytest.compat import LEGACY_PATH
 from _pytest.compat import NOTSET
 from _pytest.compat import safe_getattr
@@ -57,7 +56,6 @@
 from _pytest.fixtures import FuncFixtureInfo
 from _pytest.fixtures import get_scope_node
 from _pytest.main import Session
-from _pytest.mark import MARK_GEN
 from _pytest.mark import ParameterSet
 from _pytest.mark.structures import get_unpacked_marks
 from _pytest.mark.structures import Mark
@@ -231,16 +229,13 @@
  lineno=lineno + 1,
  )
  elif getattr(obj, "__test__", True):
- if is_generator(obj):
- res = Function.from_parent(collector, name=name)
- reason = (
- f"yield tests were removed in pytest 4.0 - {name} will be ignored"
+ if inspect.isgeneratorfunction(obj):
+ fail(
+  f"'yield' keyword is allowed in fixtures, but not in tests ({name})",
+ pytrace=False,
  )
- res.add_marker(MARK_GEN.xfail(run=False, reason=reason))
- res.warn(PytestCollectionWarning(reason))
- return res
- else:
- return list(collector._genfunctions(name, obj))
+ return list(collector._genfunctions(name, obj))
+ return None
  return None
 
 

testing/test_collection.py

@@ -1878,3 +1878,20 @@ def test_respect_system_exceptions(
  result.stdout.fnmatch_lines([f"*{head}*"])
  result.stdout.fnmatch_lines([msg])
  result.stdout.no_fnmatch_line(f"*{tail}*")
+
+
+def test_yield_disallowed_in_tests(pytester: Pytester):
+ """Ensure generator test functions with 'yield' fail collection (#12960)."""
+ pytester.makepyfile(
+ """
+ def test_with_yield():
+ yield 1
+ """
+ )
+ result = pytester.runpytest()
+ assert result.ret == 2
+ result.stdout.fnmatch_lines(
+ ["*'yield' keyword is allowed in fixtures, but not in tests (test_with_yield)*"]
+ )
+ # Assert that no tests were collected
+ result.stdout.fnmatch_lines(["*collected 0 items*"])

testing/test_compat.py

@@ -5,35 +5,21 @@
 from functools import cached_property
 from functools import partial
 from functools import wraps
-import sys
 from typing import TYPE_CHECKING
 
 from _pytest.compat import _PytestWrapper
 from _pytest.compat import assert_never
 from _pytest.compat import get_real_func
-from _pytest.compat import is_generator
 from _pytest.compat import safe_getattr
 from _pytest.compat import safe_isclass
 from _pytest.outcomes import OutcomeException
-from _pytest.pytester import Pytester
 import pytest
 
 
 if TYPE_CHECKING:
  from typing_extensions import Literal
 
 
-def test_is_generator() -> None:
- def zap():
- yield # pragma: no cover
-
- def foo():
- pass # pragma: no cover
-
- assert is_generator(zap)
- assert not is_generator(foo)
-
-
 def test_real_func_loop_limit() -> None:
  class Evil:
  def __init__(self):
@@ -95,65 +81,6 @@ def foo(x):
  assert get_real_func(partial(foo)) is foo
 
 
-@pytest.mark.skipif(sys.version_info >= (3, 11), reason="coroutine removed")
-def test_is_generator_asyncio(pytester: Pytester) -> None:
- pytester.makepyfile(
- """
- from _pytest.compat import is_generator
- import asyncio
- @asyncio.coroutine
- def baz():
- yield from [1,2,3]
-
- def test_is_generator_asyncio():
- assert not is_generator(baz)
- """
- )
- # avoid importing asyncio into pytest's own process,
- # which in turn imports logging (#8)
- result = pytester.runpytest_subprocess()
- result.stdout.fnmatch_lines(["*1 passed*"])
-
-
-def test_is_generator_async_syntax(pytester: Pytester) -> None:
- pytester.makepyfile(
- """
- from _pytest.compat import is_generator
- def test_is_generator_py35():
- async def foo():
- await foo()
-
- async def bar():
- pass
-
- assert not is_generator(foo)
- assert not is_generator(bar)
- """
- )
- result = pytester.runpytest()
- result.stdout.fnmatch_lines(["*1 passed*"])
-
-
-def test_is_generator_async_gen_syntax(pytester: Pytester) -> None:
- pytester.makepyfile(
- """
- from _pytest.compat import is_generator
- def test_is_generator():
- async def foo():
- yield
- await foo()
-
- async def bar():
- yield
-
- assert not is_generator(foo)
- assert not is_generator(bar)
- """
- )
- result = pytester.runpytest()
- result.stdout.fnmatch_lines(["*1 passed*"])
-
-
 class ErrorsHelper:
  @property
  def raise_baseexception(self):

testing/test_terminal.py

@@ -1042,10 +1042,6 @@ def test_pass():
  class TestClass(object):
  def test_skip(self):
  pytest.skip("hello")
- def test_gen():
- def check(x):
- assert x == 1
- yield check, 0
  """
  )
 
@@ -1058,7 +1054,6 @@ def test_verbose_reporting(self, verbose_testfile, pytester: Pytester) -> None:
  "*test_verbose_reporting.py::test_fail *FAIL*",
  "*test_verbose_reporting.py::test_pass *PASS*",
  "*test_verbose_reporting.py::TestClass::test_skip *SKIP*",
- "*test_verbose_reporting.py::test_gen *XFAIL*",
  ]
  )
  assert result.ret == 1