chore(tests): add project TestCase (#69)

Add a project `TestCase` that extends `unittest.TestCase` to provide the following:

- Configure the execution environment at the class level, once for the whole `TestCase`. This is similar to calling `app.setup`.
- Add a class method, `config_factory` that returns an `app.lib.Config` instance used to configure the execution environment of this `TestCase` instances.

All existing unit tests have also been refactored to extend from this TestCase. Included also are minor bug fixes and improvements.

.config.template.yaml

@@ -6,7 +6,7 @@
 # allows the app to communicate with the remote IDR Server and for data
 # exchange to happen.
 # This is a required setting.
-DEFAULT_TRANSPORT_FACTORY: "app.lib.transports.http.http_transport_factory"
+DEFAULT_TRANSPORT_FACTORY: app.lib.transports.http.http_transport_factory
 
 # The logging configuration for the app. This app use Python's built it logging.
 # https://docs.python.org/3/library/logging.html
@@ -25,12 +25,14 @@ LOGGING:
       format: "%(levelname)s: %(asctime)s %(module)s %(process)d %(thread)d %(message)s"
   handlers:
     console:
-      level: "DEBUG"
-      class: "logging.StreamHandler"
-      formatter: "verbose"
-  root:
-    level: "INFO"
-    handlers": [ "console" ]
+      level: DEBUG
+      class: logging.StreamHandler
+      formatter: verbose
+  loggers:
+    app:
+      level: INFO
+      handlers:
+        - console
 
 # The retry module global configuration. The values here will be used for each
 # retry instance when not specified.
@@ -47,7 +49,7 @@ RETRY:
 # on that data including what is uploaded to the server.
 # This setting is not required and defaults to an empty list.
 #SUPPORTED_DATA_SOURCE_TYPES:
-#  - "app.imp.sql_data.SQLDataSourceType"
+#  - app.imp.sql_data.SQLDataSourceType
 
 
 
@@ -58,13 +60,13 @@ RETRY:
 # Configuration specific to the HTTPTransport.
 # This is only required if HTTPTransport is set as the default Transport.
 HTTP_TRANSPORT:
-  default_http_api_dialect_factory: "app.lib.transports.http.idr_server_api_v1_dialect_factory"
+  default_http_api_dialect_factory: app.lib.transports.http.idr_server_api_v1_dialect_factory
   connect_timeout: 60  # 1 minutes
   read_timeout: 60 # 1 minute
 
 # A function that when called should return a HTTPAPIDialect.
 # This is only required if HTTPTransport is set as the default Transport.
-DEFAULT_HTTP_API_DIALECT_FACTORY: "app.lib.http.idr_server_api_v1_dialect_factory"
+DEFAULT_HTTP_API_DIALECT_FACTORY: app.lib.http.idr_server_api_v1_dialect_factory
 
 # The configuration of the backend to this app. This setting is used by HTTP
 # API dialects.
@@ -84,10 +86,10 @@ REMOTE_SERVER:
 # MySQL databases.
 # This is only required if the SQLDataSourceType is in use.
 MYSQL_DB_INSTANCE:
-  host: "localhost"
+  host: localhost
   port: 3306
-  username: "idr_client"
-  password: "securePa$$word"
+  username: idr_client
+  password: securePa$$word
 
 
 
@@ -100,6 +102,6 @@ MYSQL_DB_INSTANCE:
 # location data is composed of a unique code for ease of indexing and a
 # human-readable name.
 # Both of these settings are required.
-ORG_UNIT_CODE: "12345"
+ORG_UNIT_CODE: 12345
 
-ORG_UNIT_NAME: "Test Facility"
+ORG_UNIT_NAME: Test Facility

app/__init__.py

@@ -37,7 +37,7 @@
             "verbose": {
                 "format": (
                     "%(levelname)s: %(asctime)s %(module)s "
-                    "%(process)d %(thread)d %(message)s"
+                    "%(process)d %(message)s"
                 ),
             },
         },
@@ -48,7 +48,9 @@
                 "formatter": "verbose",
             },
         },
-        "root": {"level": "INFO", "handlers": ["console"]},
+        "loggers": {
+            "app": {"level": "INFO", "handlers": ["console"]},
+        },
     },
     _SETTINGS_INITIALIZERS_CONFIG_KEY: [],
     _SUPPORTED_DATA_SOURCE_TYPES_CONFIG_KEY: [],
@@ -231,6 +233,11 @@ def setup(
     """
     Set up the application and ready it for use.
 
+    This involves configuring the settings and app registry, configuring
+    logging, loading supported
+    :class:`data source types <app.core.DataSourceType>` and initializing the
+    default :class:`transport <app.core.Transport>`.
+
     :param initial_settings: Optional configuration parameters to override the
         defaults.
     :param settings_initializers:
@@ -255,6 +262,8 @@ def setup(
             _settings_dict.get(_SETTINGS_INITIALIZERS_CONFIG_KEY, ()),
         ),
     )
+    # FIXME: This is hardcoded default behaviour and it's problematic to test
+    #  or mock properly.
     _initializers.insert(0, _LoggingInitializer())
     _initializers.insert(1, _SupportedDataSourceTypesInitializer())
     _initializers.insert(2, _DefaultTransportFactoryInitializer())

app/lib/transports/http/__init__.py

@@ -80,5 +80,6 @@ def http_transport_factory() -> HTTPTransport:
     "HTTPAPIDialect",
     "HTTPTransport",
     "IDRServerAPIv1",
+    "http_transport_factory",
     "idr_server_api_v1_dialect_factory",
 ]

tests/__init__.py

@@ -0,0 +1,56 @@
+from unittest import TestCase as _TestCase
+from unittest.mock import patch
+
+from app.lib import AppRegistry, Config
+
+from .factories import config_factory as _cf
+
+
+class TestCase(_TestCase):
+    """A project-specific ``TestCase``.
+
+    Extend the default :class:`unittest.TestCase` to provide the following:
+
+    * Configure the execution environment at the class level, once for the
+      whole ``TestCase``. This is similar to calling :func:`app.setup`.
+    * Add a class method, :meth:`config_factory` that returns a
+      :class:`Config <app.lib.Config>` instance used to configure the
+      execution environment of this ``TestCase`` instances.
+    """
+
+    @classmethod
+    def config_factory(cls) -> Config:
+        """Return a ``Config`` instance.
+
+        Return a :class:`Config <app.lib.Config>` instance used to configure
+        the execution environment of this ``TestCase`` instances.
+
+        :return: a Config instance.
+        """
+        return Config(settings=_cf())
+
+    @classmethod
+    def setUpClass(cls) -> None:
+        """Set up class fixture before running the tests in the class.
+
+        Extend the default implementation by setting up a patch for the
+        application settings and registry using the value returned by the
+        :meth:`config_factory` class method. The patch is accessible through
+        the class attribute :attr:`config_patch` for interested subclasses.
+
+        .. warning::
+            It is highly encouraged that subclasses extending this method call
+            ``super()`` to avoid weird, unpredictable behaviour during test
+            runs caused by misconfigured execution environments.
+
+        :return: None.
+        """
+        super().setUpClass()
+        config_patcher = patch.multiple(
+            "app",
+            registry=AppRegistry(),
+            settings=cls.config_factory(),
+        )
+        config_patcher.start()
+        cls.config_patcher = config_patcher
+        cls.addClassCleanup(config_patcher.stop)

tests/core/test_domain.py

@@ -1,8 +1,7 @@
-from unittest import TestCase
-
 import pytest
 
 from app.core import AbstractDomainObject, IdentifiableDomainObject
+from tests import TestCase
 
 from .factories import (
     FakeDataSource,

tests/core/test_exceptions.py

@@ -1,6 +1,5 @@
-from unittest import TestCase
-
 from app.core import IDRClientException
+from tests import TestCase
 
 
 class TestIDRClientException(TestCase):

tests/imp/sql_data/test_domain.py

@@ -1,6 +1,5 @@
 import os
 from typing import TYPE_CHECKING, Any
-from unittest import TestCase
 from unittest.mock import patch
 
 import pytest
@@ -18,6 +17,7 @@
     SupportedDBVendors,
 )
 from app.lib import Config, ImproperlyConfiguredError
+from tests import TestCase
 
 from .factories import (
     SQLDataSourceFactory,

tests/lib/config/test_config.py

@@ -1,9 +1,9 @@
 from typing import TYPE_CHECKING, Any
-from unittest import TestCase
 
 import pytest
 
 from app.lib import Config, MissingSettingError, SettingInitializer
+from tests import TestCase
 
 if TYPE_CHECKING:
     from collections.abc import Mapping, Sequence

tests/lib/retry/test_retry.py

@@ -1,5 +1,4 @@
 from datetime import datetime, timedelta
-from unittest import TestCase
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -12,6 +11,7 @@
     if_exception_type_factory,
     if_idr_exception,
 )
+from tests import TestCase
 
 
 def test_if_idr_exception() -> None:
@@ -54,10 +54,7 @@ def setUp(self) -> None:
         self._patch.start()
         self._instance: Retry = Retry()
         self._instance.load_config()
-
-    def tearDown(self) -> None:
-        super().tearDown()
-        self._patch.stop()
+        self.addCleanup(self._patch.stop)
 
     def test_calculate_deadline_time_return_value_with_no_deadline(
         self,

tests/lib/retry/test_setting_initializers.py

@@ -1,9 +1,8 @@
-from unittest import TestCase
-
 import pytest
 
 from app.lib import ImproperlyConfiguredError, RetryInitializer
 from app.lib.retry.constants import DEFAULT_RETRY_CONFIG
+from tests import TestCase
 
 
 class TestRetryInitializer(TestCase):
@@ -41,6 +40,6 @@ def test_execute_when_invalid_config_is_provided(self) -> None:
                 self._instance.execute({setting: "-0.1"})  # type: ignore
 
     def test_setting_property_return_value(self) -> None:
-        """Assert the the ``setting`` property returns the expected value."""
+        """Assert the ``setting`` property returns the expected value."""
 
         assert self._instance.setting == "RETRY"

tests/lib/tasks/test_common.py

@@ -1,10 +1,10 @@
 from typing import TYPE_CHECKING
-from unittest import TestCase
 
 import pytest
 
 from app.core import Task
 from app.lib import Chainable, Consumer, Pipeline
+from tests import TestCase
 
 if TYPE_CHECKING:
     from collections.abc import Callable

tests/lib/tasks/test_concurrent.py

@@ -1,12 +1,12 @@
 from concurrent.futures import Executor, ThreadPoolExecutor, wait
 from typing import TYPE_CHECKING
-from unittest import TestCase
 
 import pytest
 
 from app.core import Task
 from app.lib import ConcurrentExecutor, completed_successfully
 from app.lib.tasks.concurrent import ConcurrentExecutorDisposedError
+from tests import TestCase
 
 if TYPE_CHECKING:
     from collections.abc import Sequence

tests/lib/tasks/test_sql.py

@@ -1,5 +1,4 @@
 from typing import TYPE_CHECKING
-from unittest import TestCase
 from unittest.mock import patch
 
 import pytest
@@ -8,6 +7,7 @@
 
 from app.core import ExtractionOperationError
 from app.lib import SimpleSQLSelect
+from tests import TestCase
 
 if TYPE_CHECKING:
     from pandas import DataFrame

tests/lib/test_app_registry.py

@@ -1,11 +1,11 @@
 from typing import TYPE_CHECKING
-from unittest import TestCase
 
 import pytest
 
 from app.imp.sql_data import SQLDataSourceType
 from app.lib import AppRegistry, ImproperlyConfiguredError
 from app.lib.transports.http import http_transport_factory
+from tests import TestCase
 
 if TYPE_CHECKING:
     from collections.abc import Mapping

tests/lib/transports/http/test_api_v1_dialect.py

@@ -1,6 +1,5 @@
 import json
 from typing import TYPE_CHECKING, Any
-from unittest import TestCase
 from unittest.mock import patch
 
 import pytest
@@ -10,6 +9,7 @@
     IDRServerAPIv1,
     idr_server_api_v1_dialect_factory,
 )
+from tests import TestCase
 from tests.core.factories import (
     FakeDataSourceFactory,
     FakeDataSourceTypeFactory,

tests/lib/transports/http/test_http.py

@@ -1,12 +1,11 @@
 from typing import Any
-from unittest import TestCase
 from unittest.mock import patch
 
 import pytest
 
-import app
 from app.lib import ImproperlyConfiguredError
 from app.lib.transports.http import HTTPTransport, http_transport_factory
+from tests import TestCase
 from tests.factories import config_factory
 
 
@@ -32,10 +31,10 @@ def test_http_transport_factory_with_valid_settings_works(self) -> None:
         Assert that a http transport factory returns the expected value with
         a valid config.
         """
-        app.setup(initial_settings=self._app_config)
-        transport: HTTPTransport = http_transport_factory()
+        with patch("app.settings", self._app_config):
+            transport: HTTPTransport = http_transport_factory()
 
-        assert transport is not None
+            assert transport is not None
 
     def test_http_transport_factory_with_invalid_settings_fails(self) -> None:
         """

tests/lib/transports/http/test_http_transport.py

@@ -1,11 +1,11 @@
-from unittest import TestCase
 from unittest.mock import patch
 
 import pytest
 from requests.exceptions import ChunkedEncodingError, ConnectionError
 
 from app.core import TransportClosedError, TransportError
 from app.lib.transports.http import HTTPAPIDialect, HTTPTransport
+from tests import TestCase
 from tests.core.factories import (
     FakeDataSourceFactory,
     FakeDataSourceTypeFactory,
@@ -63,8 +63,8 @@ def test_dispose_returns_cleanly(self) -> None:
 
     def test_a_disposed_transport_raises_expected_errors(self) -> None:
         """
-        Assert that a disposed transport raises ``TransportClosedError`` on
-        attempted usage.
+        Assert that a disposed Transport instance raises
+        ``TransportClosedError`` on attempted usage.
         """
         data_source = FakeDataSourceFactory()
         data_source_type = FakeDataSourceTypeFactory()