test(observability): add test-only environment variable overrides and refactor tests

Author: chalmerlowe

packages/google-api-core/google/api_core/observability/__init__.py

@@ -1,9 +1,22 @@
-from .options import is_signal_enabled
+from .options import (
+    clear_test_env_overrides,
+    is_signal_enabled,
+    set_test_env_override,
+)
 
 try:
     # Tell flake8 that it's okay this is unused, it's just being exposed to the package namespace.
     from .tracing import OtelSpanEnricher  # noqa: F401
 
-    __all__ = ["is_signal_enabled", "OtelSpanEnricher"]
+    __all__ = [
+        "is_signal_enabled",
+        "set_test_env_override",
+        "clear_test_env_overrides",
+        "OtelSpanEnricher",
+    ]
 except ImportError:
-    __all__ = ["is_signal_enabled"]
+    __all__ = [
+        "is_signal_enabled",
+        "set_test_env_override",
+        "clear_test_env_overrides",
+    ]

packages/google-api-core/google/api_core/observability/options.py

@@ -21,8 +21,31 @@ def _strtobool(val: str) -> Optional[bool]:
     raise ValueError(f"Invalid truth value: {val!r}")
 
 
+_TEST_ENV_OVERRIDES: Dict[str, bool] = {}
+
+
+def set_test_env_override(name: str, value: Optional[bool]) -> None:
+    """Sets a test-only override for a specific environment variable.
+
+    This is intended ONLY for unit/integration testing to prevent mutating
+    os.environ.
+    """
+    if value is None:
+        _TEST_ENV_OVERRIDES.pop(name, None)
+    else:
+        _TEST_ENV_OVERRIDES[name] = value
+
+
+def clear_test_env_overrides() -> None:
+    """Clears all test-only overrides."""
+    _TEST_ENV_OVERRIDES.clear()
+
+
 def _get_env_bool(name: str) -> Optional[bool]:
     """Retrieve the boolean value of an environment variable."""
+    if name in _TEST_ENV_OVERRIDES:
+        return _TEST_ENV_OVERRIDES[name]
+
     val = os.getenv(name)
     if val is None:
         return None

packages/google-api-core/tests/unit/observability/test_options.py

@@ -1,6 +1,72 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 import pytest
 
 from google.api_core.observability import options
+from google.api_core.observability.options import (
+    _get_env_bool,
+    _strtobool,
+    clear_test_env_overrides,
+    set_test_env_override,
+)
+
+
+@pytest.fixture(autouse=True)
+def clean_overrides():
+    yield
+    clear_test_env_overrides()
+
+
+@pytest.mark.parametrize(
+    "value,expected",
+    [
+        ("y", True),
+        ("yes", True),
+        ("t", True),
+        ("true", True),
+        ("on", True),
+        ("1", True),
+        ("n", False),
+        ("no", False),
+        ("f", False),
+        ("false", False),
+        ("off", False),
+        ("0", False),
+        ("  True  ", True),
+        (" FALSE ", False),
+        ("", None),
+    ],
+)
+def test_strtobool(value, expected):
+    assert _strtobool(value) is expected
+
+
+def test_strtobool_invalid():
+    with pytest.raises(ValueError):
+        _strtobool("invalid")
+
+
+def test_get_env_bool(monkeypatch):
+    monkeypatch.setenv("TEST_VAR", "true")
+    assert _get_env_bool("TEST_VAR") is True
+
+    monkeypatch.setenv("TEST_VAR", "invalid")
+    assert _get_env_bool("TEST_VAR") is None
+
+    monkeypatch.delenv("TEST_VAR", raising=False)
+    assert _get_env_bool("TEST_VAR") is None
 
 
 @pytest.mark.parametrize(
@@ -10,58 +76,56 @@
         ({}, None, False, False),
         ({}, None, True, True),
         # Service-specific env var
-        ({"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": "true"}, None, False, True),
-        ({"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": "false"}, None, True, False),
+        ({"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": True}, None, False, True),
+        ({"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": False}, None, True, False),
         # Experimental fallback
         (
-            {"GOOGLE_CLOUD_EXPERIMENTAL_PYTHON_TRANSLATE_TRACES_ENABLED": "true"},
+            {"GOOGLE_CLOUD_EXPERIMENTAL_PYTHON_TRANSLATE_TRACES_ENABLED": True},
             None,
             False,
             True,
         ),
         # Precedence: Service specific overrides global
         (
             {
-                "GOOGLE_CLOUD_PYTHON_TRACES_ENABLED": "true",
-                "GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": "false",
+                "GOOGLE_CLOUD_PYTHON_TRACES_ENABLED": True,
+                "GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": False,
             },
             None,
             False,
             False,
         ),
         (
             {
-                "GOOGLE_CLOUD_PYTHON_TRACES_ENABLED": "false",
-                "GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": "true",
+                "GOOGLE_CLOUD_PYTHON_TRACES_ENABLED": False,
+                "GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": True,
             },
             None,
             False,
             True,
         ),
         # Precedence: Client options override env vars
         (
-            {"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": "false"},
+            {"GOOGLE_CLOUD_PYTHON_TRANSLATE_TRACES_ENABLED": False},
             {"enable_traces": True},
             False,
             True,
         ),
     ],
 )
-def test_is_signal_enabled(
-    monkeypatch, env_vars, client_options, default_val, expected
-):
-    # Setup environment variables using pytest's monkeypatch fixture
+def test_is_signal_enabled(env_vars, client_options, default_val, expected):
+    # Setup environment variables using our test overrides
     for k, v in env_vars.items():
-        monkeypatch.setenv(k, v)
+        set_test_env_override(k, v)
 
     result = options.is_signal_enabled(
         "translate", "traces", client_options=client_options, default=default_val
     )
     assert result is expected
 
 
-def test_legacy_var_with_warning(monkeypatch):
-    monkeypatch.setenv("LEGACY_TRACE_VAR", "true")
+def test_legacy_var_with_warning():
+    set_test_env_override("LEGACY_TRACE_VAR", True)
 
     with pytest.warns(DeprecationWarning, match="LEGACY_TRACE_VAR"):
         result = options.is_signal_enabled(