Don't allow environment variables to be set during test runs

Author: asmeurer

array_api_strict/_flags.py

@@ -293,6 +293,13 @@ def __exit__(self, exc_type, exc_value, traceback):
 
 # Private functions
 
+ENVIRONMENT_VARIABLES = [
+    "ARRAY_API_STRICT_API_VERSION",
+    "ARRAY_API_STRICT_BOOLEAN_INDEXING",
+    "ARRAY_API_STRICT_DATA_DEPENDENT_SHAPES",
+    "ARRAY_API_STRICT_ENABLED_EXTENSIONS",
+]
+
 def set_flags_from_environment():
     if "ARRAY_API_STRICT_API_VERSION" in os.environ:
         set_array_api_strict_flags(

array_api_strict/tests/conftest.py

@@ -1,7 +1,14 @@
-from .._flags import reset_array_api_strict_flags
+import os
+
+from .._flags import reset_array_api_strict_flags, ENVIRONMENT_VARIABLES
 
 import pytest
 
+def pytest_sessionstart(session):
+    for env_var in ENVIRONMENT_VARIABLES:
+        if env_var in os.environ:
+            pytest.exit(f"ERROR: {env_var} is set. array-api-strict environment variables must not be set when the tests are run.")
+
 @pytest.fixture(autouse=True)
 def reset_flags():
     reset_array_api_strict_flags()