add W6401 deprecated-pytest-yield-fixture

Author: reverbc

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+- W6401 `deprecated-pytest-yield-fixture`: add warning for [yield_fixture functions](https://docs.pytest.org/en/latest/yieldfixture.html)
 
 ## [0.2.0] - 2020-05-25
 ### Added

README.md

@@ -84,6 +84,20 @@ class TestClass(object):
         assert self.defined_in_setup_class  # <- Instance of 'TestClass' has no 'defined_in_setup_class' member
 ```
 
+## Raise new warning(s)
+
+### W6401 `deprecated-pytest-yield-fixture`
+
+Raise when using deprecated `@pytest.yield_fixture` decorator ([ref](https://docs.pytest.org/en/latest/yieldfixture.html))
+
+```python
+import pytest
+
+@pytest.yield_fixture  # <- Using a deprecated @pytest.yield_fixture decorator
+def yield_fixture():
+    yield
+```
+
 ## Changelog
 
 See [CHANGELOG](CHANGELOG.md).

pylint_pytest/checkers/fixture_loader.py renamed to pylint_pytest/checkers/fixture.py

@@ -5,7 +5,7 @@
 from pylint.checkers.variables import VariablesChecker
 from pylint.interfaces import IAstroidChecker
 import pytest
-from ..utils import _can_use_fixture, _is_same_module, _is_pytest_mark_usefixtures
+from ..utils import _can_use_fixture, _is_same_module, _is_pytest_mark_usefixtures, _is_pytest_fixture
 from . import BasePytestChecker
 
 
@@ -17,9 +17,15 @@ def pytest_sessionfinish(self, session):
         self.fixtures = session._fixturemanager._arg2fixturedefs
 
 
-class FixtureLoader(BasePytestChecker):
+class FixtureChecker(BasePytestChecker):
     __implements__ = IAstroidChecker
-    msgs = {'E6401': ('', 'pytest-fixture-loader', '')}
+    msgs = {
+        'W6401': (
+            'Using a deprecated @pytest.yield_fixture decorator',
+            'deprecated-pytest-yield-fixture',
+            'Used when using a deprecated pytest decorator that has been deprecated in pytest-3.0'
+        ),
+    }
 
     _pytest_fixtures = {}
     _invoked_with_func_args = set()
@@ -28,19 +34,19 @@ class FixtureLoader(BasePytestChecker):
 
     def open(self):
         # patch VariablesChecker.add_message
-        FixtureLoader._original_add_message = VariablesChecker.add_message
-        VariablesChecker.add_message = FixtureLoader.patch_add_message
+        FixtureChecker._original_add_message = VariablesChecker.add_message
+        VariablesChecker.add_message = FixtureChecker.patch_add_message
 
     def close(self):
         '''restore & reset class attr for testing'''
         # restore add_message
-        VariablesChecker.add_message = FixtureLoader._original_add_message
-        FixtureLoader._original_add_message = callable
+        VariablesChecker.add_message = FixtureChecker._original_add_message
+        FixtureChecker._original_add_message = callable
 
         # reset fixture info storage
-        FixtureLoader._pytest_fixtures = {}
-        FixtureLoader._invoked_with_func_args = set()
-        FixtureLoader._invoked_with_usefixtures = set()
+        FixtureChecker._pytest_fixtures = {}
+        FixtureChecker._invoked_with_func_args = set()
+        FixtureChecker._invoked_with_usefixtures = set()
 
     def visit_module(self, node):
         '''
@@ -49,13 +55,13 @@ def visit_module(self, node):
         - create containers for the module to store args and fixtures
         '''
         # storing all fixtures discovered by pytest session
-        FixtureLoader._pytest_fixtures = {}  # Dict[List[_pytest.fixtures.FixtureDef]]
+        FixtureChecker._pytest_fixtures = {}  # Dict[List[_pytest.fixtures.FixtureDef]]
 
         # storing all used function arguments
-        FixtureLoader._invoked_with_func_args = set()  # Set[str]
+        FixtureChecker._invoked_with_func_args = set()  # Set[str]
 
         # storing all invoked fixtures through @pytest.mark.usefixture(...)
-        FixtureLoader._invoked_with_usefixtures = set()  # Set[str]
+        FixtureChecker._invoked_with_usefixtures = set()  # Set[str]
 
         try:
             with open(os.devnull, 'w') as devnull:
@@ -69,7 +75,7 @@ def visit_module(self, node):
                     [node.file, '--fixtures'],
                     plugins=[fixture_collector],
                 )
-                FixtureLoader._pytest_fixtures = fixture_collector.fixtures
+                FixtureChecker._pytest_fixtures = fixture_collector.fixtures
         finally:
             # restore output devices
             sys.stdout, sys.stderr = stdout, stderr
@@ -87,6 +93,10 @@ def visit_functiondef(self, node):
                         # save all visited fixtures
                         for arg in decorator.args:
                             self._invoked_with_usefixtures.add(arg.value)
+                    if int(pytest.__version__.split('.')[0]) >= 3 and \
+                            _is_pytest_fixture(decorator, fixture=False):
+                        # raise deprecated warning for @pytest.yield_fixture
+                        self.add_message('deprecated-pytest-yield-fixture', node=node)
             for arg in node.args.args:
                 self._invoked_with_func_args.add(arg.name)
 
@@ -109,17 +119,17 @@ def patch_add_message(self, msgid, line=None, node=None, args=None,
                 pass
 
             # imported fixture is referenced in test/fixture func
-            elif fixture_name in FixtureLoader._invoked_with_func_args \
-                    and fixture_name in FixtureLoader._pytest_fixtures:
-                if _is_same_module(fixtures=FixtureLoader._pytest_fixtures,
+            elif fixture_name in FixtureChecker._invoked_with_func_args \
+                    and fixture_name in FixtureChecker._pytest_fixtures:
+                if _is_same_module(fixtures=FixtureChecker._pytest_fixtures,
                                    import_node=node,
                                    fixture_name=fixture_name):
                     return
 
             # fixture is referenced in @pytest.mark.usefixtures
-            elif fixture_name in FixtureLoader._invoked_with_usefixtures \
-                    and fixture_name in FixtureLoader._pytest_fixtures:
-                if _is_same_module(fixtures=FixtureLoader._pytest_fixtures,
+            elif fixture_name in FixtureChecker._invoked_with_usefixtures \
+                    and fixture_name in FixtureChecker._pytest_fixtures:
+                if _is_same_module(fixtures=FixtureChecker._pytest_fixtures,
                                    import_node=node,
                                    fixture_name=fixture_name):
                     return
@@ -128,20 +138,20 @@ def patch_add_message(self, msgid, line=None, node=None, args=None,
         if msgid == 'unused-argument' and \
                 _can_use_fixture(node.parent.parent) and \
                 isinstance(node.parent, astroid.Arguments) and \
-                node.name in FixtureLoader._pytest_fixtures:
+                node.name in FixtureChecker._pytest_fixtures:
             return
 
         # check W0621 redefined-outer-name
         if msgid == 'redefined-outer-name' and \
                 _can_use_fixture(node.parent.parent) and \
                 isinstance(node.parent, astroid.Arguments) and \
-                node.name in FixtureLoader._pytest_fixtures:
+                node.name in FixtureChecker._pytest_fixtures:
             return
 
         if int(pylint.__version__.split('.')[0]) >= 2:
-            FixtureLoader._original_add_message(
+            FixtureChecker._original_add_message(
                 self, msgid, line, node, args, confidence, col_offset)
         else:
             # python2 + pylint1.9 backward compatibility
-            FixtureLoader._original_add_message(
+            FixtureChecker._original_add_message(
                 self, msgid, line, node, args, confidence)

pylint_pytest/utils.py

@@ -15,8 +15,15 @@ def _is_pytest_mark_usefixtures(decorator):
     return False
 
 
-def _is_pytest_fixture(decorator):
+def _is_pytest_fixture(decorator, fixture=True, yield_fixture=True):
     attr = None
+    to_check = set()
+
+    if fixture:
+        to_check.add('fixture')
+
+    if yield_fixture:
+        to_check.add('yield_fixture')
 
     try:
         if isinstance(decorator, astroid.Attribute):
@@ -27,7 +34,7 @@ def _is_pytest_fixture(decorator):
             # expecting @pytest.fixture(scope=...)
             attr = decorator.func
 
-        if attr and attr.attrname in ('fixture', 'yield_fixture') \
+        if attr and attr.attrname in to_check \
                 and attr.expr.name == 'pytest':
             return True
     except AttributeError:

tests/input/deprecated-pytest-yield-fixture/func.py

@@ -0,0 +1,11 @@
+import pytest
+
+
+@pytest.yield_fixture()
+def yield_fixture():
+    yield
+
+
+@pytest.yield_fixture(scope='session')
+def yield_fixture_session():
+    yield

tests/input/deprecated-pytest-yield-fixture/smoke.py

@@ -0,0 +1,6 @@
+import pytest
+
+
+@pytest.yield_fixture
+def yield_fixture():
+    yield

tests/test_pytest_yield_fixture.py

@@ -0,0 +1,16 @@
+from base_tester import BasePytestTester
+from pylint_pytest.checkers.fixture import FixtureChecker
+
+
+class TestDeprecatedPytestYieldFixture(BasePytestTester):
+    CHECKER_CLASS = FixtureChecker
+    IMPACTED_CHECKER_CLASSES = []
+    MSG_ID = 'deprecated-pytest-yield-fixture'
+
+    def test_smoke(self):
+        self.run_linter(enable_plugin=True)
+        self.verify_messages(1)
+
+    def test_func(self):
+        self.run_linter(enable_plugin=True)
+        self.verify_messages(2)

tests/test_redefined_outer_name.py

@@ -1,11 +1,11 @@
 import pytest
 from pylint.checkers.variables import VariablesChecker
 from base_tester import BasePytestTester
-from pylint_pytest.checkers.fixture_loader import FixtureLoader
+from pylint_pytest.checkers.fixture import FixtureChecker
 
 
 class TestRedefinedOuterName(BasePytestTester):
-    CHECKER_CLASS = FixtureLoader
+    CHECKER_CLASS = FixtureChecker
     IMPACTED_CHECKER_CLASSES = [VariablesChecker]
     MSG_ID = 'redefined-outer-name'
 

tests/test_regression.py

@@ -2,12 +2,12 @@
 import pytest
 from pylint.checkers.variables import VariablesChecker
 from base_tester import BasePytestTester
-from pylint_pytest.checkers.fixture_loader import FixtureLoader
+from pylint_pytest.checkers.fixture import FixtureChecker
 
 
 class TestRegression(BasePytestTester):
     '''Covering some behaviors that shouldn't get impacted by the plugin'''
-    CHECKER_CLASS = FixtureLoader
+    CHECKER_CLASS = FixtureChecker
     IMPACTED_CHECKER_CLASSES = [VariablesChecker]
     MSG_ID = 'regression'
 

tests/test_unused_argument.py

@@ -1,11 +1,11 @@
 import pytest
 from pylint.checkers.variables import VariablesChecker
 from base_tester import BasePytestTester
-from pylint_pytest.checkers.fixture_loader import FixtureLoader
+from pylint_pytest.checkers.fixture import FixtureChecker
 
 
 class TestUnusedArgument(BasePytestTester):
-    CHECKER_CLASS = FixtureLoader
+    CHECKER_CLASS = FixtureChecker
     IMPACTED_CHECKER_CLASSES = [VariablesChecker]
     MSG_ID = 'unused-argument'