Fix MyPy errors in airflow-core/tests/unit/api_fastapi/core_api/routes/public

devel-common/src/tests_common/test_utils/format_datetime.py

@@ -17,13 +17,37 @@
 from __future__ import annotations
 
 from datetime import datetime
+from typing import overload
 
 
-def from_datetime_to_zulu(dt: datetime) -> str:
-    """Format a datetime object to a string in Zulu time."""
+@overload
+def from_datetime_to_zulu(dt: datetime) -> str: ...
+@overload
+def from_datetime_to_zulu(dt: None) -> None: ...
+def from_datetime_to_zulu(dt: datetime | None) -> str | None:
+    """
+    Format a UTC datetime to an ISO-8601 Zulu string with milliseconds.
+
+    - If `dt` is None, return None (useful for optional fields in tests).
+    - This function assumes `dt` already represents UTC (e.g. tzinfo=UTC) and
+      does not perform timezone conversion.
+    """
+    if dt is None:
+        return None
     return dt.strftime("%Y-%m-%dT%H:%M:%S.%fZ")
 
 
-def from_datetime_to_zulu_without_ms(dt: datetime) -> str:
-    """Format a datetime object to a string in Zulu time without milliseconds."""
+@overload
+def from_datetime_to_zulu_without_ms(dt: datetime) -> str: ...
+@overload
+def from_datetime_to_zulu_without_ms(dt: None) -> None: ...
+def from_datetime_to_zulu_without_ms(dt: datetime | None) -> str | None:
+    """
+    Format a UTC datetime to an ISO-8601 Zulu string without milliseconds.
+
+    - If `dt` is None, return None (useful for optional fields in tests).
+    - This function assumes `dt` already represents UTC and does not convert tz.
+    """
+    if dt is None:
+        return None
     return dt.strftime("%Y-%m-%dT%H:%M:%SZ")