little update

tests/test_environment.py

@@ -0,0 +1,23 @@
+import os
+from pathlib import Path
+
+from dotenv import load_dotenv
+
+
+def test_dotenv_loads_missing_environment_value(tmp_path: Path, monkeypatch) -> None:
+    env_file = tmp_path / ".env"
+    env_file.write_text("CLOUD_PROJECT_ID=project-from-file\n")
+    monkeypatch.delenv("CLOUD_PROJECT_ID", raising=False)
+
+    assert load_dotenv(env_file) is True
+    assert os.environ["CLOUD_PROJECT_ID"] == "project-from-file"
+
+
+def test_dotenv_does_not_override_shell_environment(tmp_path: Path, monkeypatch) -> None:
+    env_file = tmp_path / ".env"
+    env_file.write_text("CLOUD_PROJECT_ID=project-from-file\n")
+    monkeypatch.setenv("CLOUD_PROJECT_ID", "project-from-shell")
+
+    load_dotenv(env_file)
+
+    assert os.environ["CLOUD_PROJECT_ID"] == "project-from-shell"