#2 suppressing FP when importing fixtures into conftest

Author: reverbc

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+### Added
+- Suppressing FP `unused-import` when fixtures defined elsewhere are imported into `conftest.py` but not directly used (#2)
+
 ## [1.0.0] - 2021-03-02
 ### Added
 - Python 3.9 support

pylint_pytest/checkers/fixture.py

@@ -71,10 +71,14 @@ def visit_module(self, node):
 
                 # run pytest session with customized plugin to collect fixtures
                 fixture_collector = FixtureCollector()
+
+                # save and restore sys.path to prevent pytest.main from altering it
+                sys_path = sys.path.copy()
                 pytest.main(
                     [node.file, '--fixtures', '--collect-only'],
                     plugins=[fixture_collector],
                 )
+                sys.path = sys_path
                 FixtureChecker._pytest_fixtures = fixture_collector.fixtures
         finally:
             # restore output devices
@@ -118,6 +122,13 @@ def patch_add_message(self, msgid, line=None, node=None, args=None,
             if message_tokens[0] == 'import' and len(message_tokens) == 2:
                 pass
 
+            # fixture is defined in other modules and being imported to
+            # conftest for pytest magic
+            elif isinstance(node.parent, astroid.Module) \
+                    and node.parent.name.split('.')[-1] == 'conftest' \
+                    and fixture_name in FixtureChecker._pytest_fixtures:
+                return
+
             # imported fixture is referenced in test/fixture func
             elif fixture_name in FixtureChecker._invoked_with_func_args \
                     and fixture_name in FixtureChecker._pytest_fixtures:

tests/base_tester.py

@@ -30,23 +30,22 @@ def run_linter(self, enable_plugin, file_path=None):
 
         with open(file_path) as fin:
             content = fin.read()
-            module = astroid.parse(content)
+            module = astroid.parse(content, module_name=module)
             module.file = fin.name
 
         self.walk(module)  # run all checkers
-        BasePytestTester.MESSAGES = self.linter.release_messages()
+        self.MESSAGES = self.linter.release_messages()
 
     def verify_messages(self, msg_count, msg_id=None):
         msg_id = msg_id or self.MSG_ID
 
         matched_count = 0
         for message in self.MESSAGES:
-            print(message)
             # only care about ID and count, not the content
             if message.msg_id == msg_id:
                 matched_count += 1
 
-        assert matched_count == msg_count
+        assert matched_count == msg_count, f'expecting {msg_count}, actual {matched_count}'
 
     def setup_method(self):
         self.linter = UnittestLinter()

tests/input/unused-import/_fixture_for_conftest.py

@@ -0,0 +1,6 @@
+import pytest
+
+
+@pytest.fixture
+def conftest_fixture_attr():
+    return True

tests/input/unused-import/conftest.py

@@ -0,0 +1 @@
+from _fixture_for_conftest import conftest_fixture_attr

tests/test_unused_import.py

@@ -32,3 +32,10 @@ def test_same_name_decorator(self, enable_plugin):
         name as fixture - should still raise unused-import warning'''
         self.run_linter(enable_plugin)
         self.verify_messages(1)
+
+    @pytest.mark.parametrize('enable_plugin', [True, False])
+    def test_conftest(self, enable_plugin):
+        '''fixtures are defined in different modules and imported to conftest
+        for pytest to do its magic'''
+        self.run_linter(enable_plugin)
+        self.verify_messages(0 if enable_plugin else 1)