fix failing logger tests (#675)

* fix [test_logger]

* test [test_logger] - mark frontend test

* fix [github/workflows] - tests: install pytest-logger plugin

* refactor [test_logger] - reset_logging: propagate `True`

Co-authored-by: Theodor <theodor@xanadu.ai>

.github/workflows/tests.yaml

@@ -47,7 +47,7 @@ jobs:
         run: |
           python3 -m pip install --upgrade pip
           pip install -r requirements-ci.txt
-          pip install wheel codecov pytest pytest-cov pytest-randomly pytest-mock --upgrade
+          pip install wheel codecov pytest pytest-cov pytest-randomly pytest-mock pytest-logger --upgrade
 
       - name: Install Strawberry Fields
         run: |

tests/frontend/test_logger.py

@@ -45,13 +45,12 @@
 """
 
 import logging
-
 import pytest
-
 import strawberryfields.engine as engine
-
 from strawberryfields.logger import logging_handler_defined, default_handler, create_logger
 
+pytestmark = pytest.mark.frontend
+
 modules_contain_logging = [engine]
 
 
@@ -63,27 +62,29 @@ def reset_logging(pytestconfig):
     logging.root.handlers = []
     root_level = logging.root.level
 
+    for module in modules_contain_logging:
+        logger = logging.getLogger(module.__name__)
+        logger.handlers = []
+        logger.setLevel(logging.NOTSET)
+        logger.propagate = True
+
     logging_plugin = pytestconfig.pluginmanager.unregister(name="logging-plugin")
 
     yield
 
+    for module in modules_contain_logging:
+        logger = logging.getLogger(module.__name__)
+        logger.handlers = []
+        logger.setLevel(logging.NOTSET)
+        logger.propagate = True
+
     logging.root.handlers[:] = root_handlers
     logging.root.setLevel(root_level)
 
     if logging_plugin:
         pytestconfig.pluginmanager.register(logging_plugin, "logging-plugin")
 
 
-@pytest.fixture(autouse=True)
-def reset_logging_module():
-    """Reset the logging specific configurations such as handlers or levels for
-    the module specific loggers."""
-    for module in modules_contain_logging:
-        logger = logging.getLogger(module.__name__)
-        logger.handlers = []
-        logger.setLevel(logging.NOTSET)
-
-
 @pytest.mark.parametrize("module", modules_contain_logging)
 class TestLogger:
     """Tests for the functions that are used to create a logger"""
@@ -120,7 +121,7 @@ class TestLoggerIntegration:
     """Tests that the SF logger integrates well with user defined logging
     configurations."""
 
-    def test_custom_configuration_without_sf_logger(self, tmpdir, caplog):
+    def test_custom_configuration_without_sf_logger(self, tmpdir):
         """Tests that if there was no SF logger created, custom logging
         configurations work as expected and no configuration details were set
         incorrectly."""
@@ -134,17 +135,17 @@ def test_custom_configuration_without_sf_logger(self, tmpdir, caplog):
         assert "A log entry." in test_file.read()
 
     @pytest.mark.parametrize("module", modules_contain_logging)
-    def test_default_sf_logger(self, module, capsys):
+    def test_default_sf_logger(self, module):
         """Tests that stderr is set for the SF logger by default as stream if
         there were not other configurations made."""
-        level = logging.DEBUG
 
         logger = create_logger(module.__name__)
         assert len(logger.handlers) == 1
-        assert logger.handlers[0].stream.name == "<stderr>"
+        # checks if stream is stderr (stream name for stderr is 8 or 9, whereas stdout 6 or 7)
+        assert logger.handlers[0].stream.fileno() in [8, 9]
 
     @pytest.mark.parametrize("module", modules_contain_logging)
-    def test_custom_logger_before_sf_logger_with_higher_level(self, module, tmpdir, caplog):
+    def test_custom_logger_before_sf_logger_with_higher_level(self, module):
         """Tests that a custom logger created before an SF logger will define
         the level for logging as expected and the SF logger does not overwrite
         the user configuration.
@@ -158,10 +159,10 @@ def test_custom_logger_before_sf_logger_with_higher_level(self, module, tmpdir,
         custom_level = logging.DEBUG
         sf_level = logging.WARNING
 
-        logger = logging.getLogger(module.__name__)
+        logger = logging.getLogger()
         logging.basicConfig(level=custom_level)
 
-        sf_logger = create_logger(module.__name__, level=sf_level)
+        _ = create_logger(module.__name__, level=sf_level)
 
         assert logging_handler_defined(logger)
         assert logger.getEffectiveLevel() == custom_level