feat: add mock_config_helper and mock_metrics test utils

shared/utils/test_utils/__init__.py

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+from .mock_config_helper import mock_config_helper
+from .mock_metrics import mock_metrics

shared/utils/test_utils/mock_config_helper.py

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+from shared.config import ConfigHelper
+
+
+def mock_config_helper(mocker, configs={}, file_configs={}):
+    """
+    Generic utility for mocking two functions on `ConfigHelper`:
+    - `get()`, which takes a config key and returns its value
+    - `load_filename_from_path()`, which takes a config key, treats its value as
+      a file path, and returns the contents of the file.
+
+    These functions underpin the non-method APIs of the config module.
+
+    Example:
+        configs = {"github.client_id": "testvalue"}
+        file_configs = {"github.integration.pem": "--------BEGIN RSA PRIVATE KEY-----..."}
+        mock_config_helper(mocker, configs, file_configs)
+
+        assert "testvalue" == get_config("github", "client_id")
+        assert "BEGIN RSA" in load_file_from_path_at_config("github", "integration", "pem")
+    """
+    orig_get = ConfigHelper.get
+    orig_load_file = ConfigHelper.load_filename_from_path
+
+    def mock_get(obj, *args, **kwargs):
+        conf_key = ".".join(args)
+        if conf_key in configs:
+            return configs.get(conf_key)
+        else:
+            return orig_get(obj, *args, **kwargs)
+
+    def mock_load_file(obj, *args, **kwargs):
+        conf_key = ".".join(args)
+        if conf_key in file_configs:
+            return file_configs.get(conf_key)
+        else:
+            return orig_load_file(obj, *args, **kwargs)
+
+    mocker.patch.object(ConfigHelper, "get", mock_get)
+    mocker.patch.object(ConfigHelper, "load_filename_from_path", mock_load_file)

shared/utils/test_utils/mock_metrics.py

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+from collections import defaultdict
+
+from shared.metrics import metrics as orig_metrics
+
+
+class MockMetrics:
+    def __init__(self, mocker):
+        self.data = defaultdict(int)
+        mocker.patch.object(orig_metrics, "incr", self._incr)
+        mocker.patch.object(orig_metrics, "decr", self._decr)
+
+    def _incr(self, stat, count=1, rate=1):
+        self.data[stat] += count
+
+    def _decr(self, stat, count=1, rate=1):
+        self.data[stat] -= count
+
+
+def mock_metrics(mocker):
+    return MockMetrics(mocker)

tests/unit/utils/test_utils/test_mock_config_helper.py

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+from shared.config import get_config, load_file_from_path_at_config
+from shared.utils.test_utils import mock_config_helper
+
+
+class TestMockConfigHelper(object):
+    def test_mock_config_helper_get(self, mocker):
+        mock_config_helper(mocker, configs={"foo.bar": "baz"})
+        assert get_config("foo", "bar", default="not baz") == "baz"
+
+    def test_mock_config_helper_load_file(self, mocker):
+        mock_config_helper(mocker, file_configs={"foo.bar": "baz"})
+        assert load_file_from_path_at_config("foo", "bar") == "baz"

tests/unit/utils/test_utils/test_mock_metrics.py

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+from shared.metrics import metrics
+from shared.utils.test_utils import mock_metrics
+
+
+class TestMockMetrics(object):
+    def test_mock_metrics_incr_decr(self, mocker):
+        m = mock_metrics(mocker)
+
+        metrics.incr("foo", count=33)
+        assert m.data["foo"] == 33
+
+        metrics.decr("foo", count=15)
+        assert m.data["foo"] == 33 - 15