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Testing Datetime Zulu Format Conversion in Apache Airflow

This test suite validates datetime formatting utilities in Apache Airflow, specifically focusing on Zulu time conversion functions. The tests ensure accurate transformation of datetime objects into standardized ISO 8601 string formats with and without millisecond precision.

Test Coverage Overview

The test coverage focuses on two primary datetime formatting functions: conversion to Zulu time with and without milliseconds. Key functionality includes:

Validation of ISO 8601 string format compliance
Handling of timezone conversions to UTC/Zulu time
Precision control for millisecond inclusion/exclusion

Implementation Analysis

The testing approach utilizes Python’s native datetime handling capabilities to verify string formatting accuracy. The implementation leverages strftime patterns to ensure consistent output formatting, with specific attention to UTC timezone representation and millisecond precision control.

Testing patterns incorporate both standard and edge cases for datetime conversions.

Technical Details

Testing tools and configuration:

Python datetime module for test data generation
Standard unit test framework
strftime format strings: ‘%Y-%m-%dT%H:%M:%S.%fZ’ and ‘%Y-%m-%dT%H:%M:%SZ’
UTC/Zulu time zone handling

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Clear separation of concerns between millisecond and non-millisecond formatting
Explicit type hinting for improved code clarity
Focused unit tests for specific formatting scenarios
Proper function documentation with clear purpose statements

apache/airflow

tests_common/test_utils/format_datetime.py

            
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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
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# 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.
from __future__ import annotations

from datetime import datetime


def from_datetime_to_zulu(dt: datetime) -> str:
    """Format a datetime object to a string in Zulu time."""
    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."""
    return dt.strftime("%Y-%m-%dT%H:%M:%SZ")