🐛 Ignore collection failures in non-tests

pylint_pytest/checkers/fixture.py

@@ -1,5 +1,5 @@
 import fnmatch
-import os
+import io
 import sys
 from pathlib import Path
 from typing import Set, Tuple
@@ -68,8 +68,8 @@ class FixtureChecker(BasePytestChecker):
         "F6401": (
             (
                 "pylint-pytest plugin cannot enumerate and collect pytest fixtures. "
-                "Please run `pytest --fixtures --collect-only path/to/current/module.py`"
-                " and resolve any potential syntax error or package dependency issues"
+                "Please run `pytest --fixtures --collect-only %s` and resolve "
+                "any potential syntax error or package dependency issues. stdout: %s. stderr: %s."
             ),
             "cannot-enumerate-pytest-fixtures",
             "Used when pylint-pytest has been unable to enumerate and collect pytest fixtures.",
@@ -118,9 +118,10 @@ def visit_module(self, node):
 
         stdout, stderr = sys.stdout, sys.stderr
         try:
-            with open(os.devnull, "w") as devnull:
+            with io.StringIO() as captured_stdout, io.StringIO() as captured_stderr:
                 # suppress any future output from pytest
-                sys.stderr = sys.stdout = devnull
+                sys.stderr = captured_stderr
+                sys.stdout = captured_stdout
 
                 # run pytest session with customized plugin to collect fixtures
                 fixture_collector = FixtureCollector()
@@ -143,8 +144,32 @@ def visit_module(self, node):
 
                 FixtureChecker._pytest_fixtures = fixture_collector.fixtures
 
-                if (ret != pytest.ExitCode.OK or fixture_collector.errors) and is_test_module:
-                    self.add_message("cannot-enumerate-pytest-fixtures", node=node)
+                legitimate_failure_paths = set(
+                    collection_report.nodeid
+                    for collection_report in fixture_collector.errors
+                    if any(
+                        fnmatch.fnmatch(
+                            Path(collection_report.nodeid).name,
+                            pattern,
+                        )
+                        for pattern in FILE_NAME_PATTERNS
+                    )
+                )
+                if (ret != pytest.ExitCode.OK or legitimate_failure_paths) and is_test_module:
+                    files_to_report = {
+                        str(Path(x).absolute().relative_to(Path.cwd()))
+                        for x in legitimate_failure_paths | {node.file}
+                    }
+
+                    self.add_message(
+                        "cannot-enumerate-pytest-fixtures",
+                        args=(
+                            " ".join(files_to_report),
+                            captured_stdout.getvalue(),
+                            captured_stderr.getvalue(),
+                        ),
+                        node=node,
+                    )
         finally:
             # restore output devices
             sys.stdout, sys.stderr = stdout, stderr

tests/test_cannot_enumerate_fixtures.py

@@ -1,3 +1,5 @@
+import re
+
 import pytest
 from base_tester import BasePytestTester
 
@@ -13,7 +15,39 @@ def test_no_such_package(self, enable_plugin):
         self.run_linter(enable_plugin)
         self.verify_messages(1 if enable_plugin else 0)
 
+        if enable_plugin:
+            msg = self.msgs[0]
+
+            # Asserts/Fixes duplicate filenames in output:
+            # https://github.com/reverbc/pylint-pytest/pull/22/files#r698204470
+            filename_arg = msg.args[0]
+            assert len(re.findall(r"\.py", filename_arg)) == 1
+
+            # Asserts that path is relative (usually to the root of the repository).
+            assert filename_arg[0] != "/"
+
+            # Assert `stdout` is non-empty.
+            assert msg.args[1]
+            # Assert `stderr` is empty (pytest runs stably, even though fixture collection fails).
+            assert not msg.args[2]
+
     @pytest.mark.parametrize("enable_plugin", [True, False])
     def test_import_corrupted_module(self, enable_plugin):
         self.run_linter(enable_plugin)
         self.verify_messages(1 if enable_plugin else 0)
+
+        if enable_plugin:
+            msg = self.msgs[0]
+
+            # ... somehow, since `import_corrupted_module.py` imports `no_such_package.py`
+            # both of their names are returned in the message.
+            filename_arg = msg.args[0]
+            assert len(re.findall(r"\.py", filename_arg)) == 2
+
+            # Asserts that paths are relative (usually to the root of the repository).
+            assert not [x for x in filename_arg.split(" ") if x[0] == "/"]
+
+            # Assert `stdout` is non-empty.
+            assert msg.args[1]
+            # Assert `stderr` is empty (pytest runs stably, even though fixture collection fails).
+            assert not msg.args[2]