Standardize event catching during repository unit tests

tests/functional/configs/test_warn_error_options.py

@@ -6,7 +6,7 @@
 from dbt.events.types import DeprecatedModel
 from dbt.tests.util import update_config_file
 from dbt_common.events.base_types import EventLevel
-from tests.functional.utils import EventCatcher
+from tests.utils import EventCatcher
 
 ModelsDictSpec = Dict[str, Union[str, "ModelsDictSpec"]]
 

tests/functional/manifest_validations/test_check_for_spaces_in_model_names.py

@@ -10,7 +10,7 @@
 )
 from dbt.tests.util import update_config_file
 from dbt_common.events.base_types import EventLevel
-from tests.functional.utils import EventCatcher
+from tests.utils import EventCatcher
 
 
 class TestSpacesInModelNamesHappyPath:

tests/unit/conftest.py

@@ -6,6 +6,7 @@
 
 # All manifest related fixtures.
 from tests.unit.utils.adapter import *  # noqa
+from tests.unit.utils.event_manager import *  # noqa
 from tests.unit.utils.manifest import *  # noqa
 from tests.unit.utils.project import *  # noqa
 

tests/unit/events/test_logging.py

@@ -0,0 +1,42 @@
+from argparse import Namespace
+from copy import deepcopy
+
+from pytest_mock import MockerFixture
+
+from dbt.events.logging import setup_event_logger
+from dbt.flags import get_flags, set_from_args
+from dbt_common.events.base_types import BaseEvent
+from dbt_common.events.event_manager_client import get_event_manager
+from dbt_common.events.logger import LoggerConfig
+from tests.utils import EventCatcher
+
+
+class TestSetupEventLogger:
+    def test_clears_preexisting_event_manager_state(self, mock_global_event_manager) -> None:
+        manager = get_event_manager()
+        manager.add_logger(LoggerConfig(name="test_logger"))
+        manager.callbacks.append(EventCatcher(BaseEvent).catch)
+        assert len(manager.loggers) == 1
+        assert len(manager.callbacks) == 1
+
+        flags = deepcopy(get_flags())
+        # setting both of these to none guarantees that no logger will be added
+        object.__setattr__(flags, "LOG_LEVEL", "none")
+        object.__setattr__(flags, "LOG_LEVEL_FILE", "none")
+
+        setup_event_logger(flags=flags)
+        assert len(manager.loggers) == 0
+        assert len(manager.callbacks) == 0
+
+    def test_specify_max_bytes(
+        self,
+        mocker: MockerFixture,
+        mock_global_event_manager,
+    ) -> None:
+        patched_file_handler = mocker.patch("dbt_common.events.logger.RotatingFileHandler")
+        args = Namespace(log_file_max_bytes=1234567)
+        set_from_args(args, {})
+        setup_event_logger(get_flags())
+        patched_file_handler.assert_called_once_with(
+            filename="logs/dbt.log", encoding="utf8", maxBytes=1234567, backupCount=5
+        )

tests/unit/test_functions.py

@@ -4,9 +4,7 @@
 
 import dbt.flags as flags
 from dbt.adapters.events.types import AdapterDeprecationWarning
-from dbt.events.logging import setup_event_logger
 from dbt.events.types import NoNodesForSelectionCriteria
-from dbt_common.events.event_manager_client import cleanup_event_logger
 from dbt_common.events.functions import msg_to_dict, warn_or_error
 from dbt_common.events.types import InfoLevel, RetryExternalCall
 from dbt_common.exceptions import EventCompilationError
@@ -83,15 +81,3 @@ def __init__(self):
         assert (
             False
         ), f"We expect `msg_to_dict` to gracefully handle exceptions, but it raised {exc}"
-
-
-def test_setup_event_logger_specify_max_bytes(mocker):
-    patched_file_handler = mocker.patch("dbt_common.events.logger.RotatingFileHandler")
-    args = Namespace(log_file_max_bytes=1234567)
-    flags.set_from_args(args, {})
-    setup_event_logger(flags.get_flags())
-    patched_file_handler.assert_called_once_with(
-        filename="logs/dbt.log", encoding="utf8", maxBytes=1234567, backupCount=5
-    )
-    # XXX if we do not clean up event logger here we are going to affect other tests.
-    cleanup_event_logger()

tests/unit/utils/event_manager.py

@@ -0,0 +1,10 @@
+import pytest
+from pytest_mock import MockerFixture
+
+from dbt_common.events.event_manager import EventManager
+
+
+@pytest.fixture
+def mock_global_event_manager(mocker: MockerFixture) -> None:
+    """Mocks the global _EVENT_MANAGER so that unit tests can safely modify it without worry about other tests."""
+    mocker.patch("dbt_common.events.event_manager_client._EVENT_MANAGER", EventManager())

tests/utils.py

@@ -0,0 +1,17 @@
+from dataclasses import dataclass, field
+from typing import List
+
+from dbt_common.events.base_types import BaseEvent, EventMsg
+
+
+@dataclass
+class EventCatcher:
+    event_to_catch: BaseEvent
+    caught_events: List[EventMsg] = field(default_factory=list)
+
+    def catch(self, event: EventMsg):
+        if event.info.name == self.event_to_catch.__name__:
+            self.caught_events.append(event)
+
+    def flush(self) -> None:
+        self.caught_events = []