Overview
The article discusses the challenges of stabilizing automated UI tests, particularly in the context of LinkedIn's iOS mobile app development. It outlines the strategies employed to reduce flaky tests and improve the reliability of the testing framework, ultimately enhancing the continuous delivery pipeline.
What You'll Learn
1
How to stabilize automated UI tests to improve reliability
2
Why flaky tests can be more detrimental than having no tests
3
How to implement a mock server to reduce dependencies in UI testing
Key Questions Answered
What strategies can be used to stabilize UI tests?
To stabilize UI tests, the article suggests implementing mock servers to minimize dependencies, using a reliable testing framework like KIF, and revising testing guidelines to ensure tests are useful, maintainable, and reliable. This approach significantly reduces the flakiness of tests and enhances the overall testing ecosystem.
Why are flaky tests considered worse than no tests?
Flaky tests can lead to a false sense of security, causing developers to revert commits unnecessarily, which can frustrate the team and lower morale. The article emphasizes that if a test cannot consistently pass, it is better to disable it rather than risk blocking development.
How did the Trunk Guardian improve test reliability?
The Trunk Guardian monitors test failures and disables flaky tests automatically, significantly reducing the rate of flaky tests from 40% to 0.1%. This proactive approach ensures that only reliable tests are run, maintaining a healthy codebase.
What is the impact of using KIF as a testing framework?
KIF, being written in Objective-C and integrated with Xcode, allows for faster and more reliable UI testing compared to previous frameworks. The article notes that after modifications, the speed of tests improved tenfold, leading to a more stable testing environment.
Key Statistics & Figures
Rate of flaky tests after implementing Trunk Guardian
0.1%
This significant reduction from a previous high of 40% demonstrates the effectiveness of the monitoring system.
Number of UI tests created
700
The article mentions that after implementing their strategies, LinkedIn successfully maintained 700 UI tests that ran stably.
Number of unit tests created
1,000
Alongside the UI tests, 1,000 unit tests were also established to ensure comprehensive coverage of code changes.
Technologies & Tools
Testing Framework
Kif
Used as the primary framework for iOS UI testing, allowing for faster and more reliable test execution.
Key Actionable Insights
1Implement mock servers in your UI testing strategy to reduce external dependencies.By using mock servers, you can isolate your tests from network and server issues, leading to more consistent test results and faster feedback loops.
2Regularly review and revise your testing guidelines to ensure they align with best practices.Establishing clear guidelines helps maintain the quality and reliability of tests, which is crucial for effective continuous integration and delivery.
3Utilize a monitoring system like Trunk Guardian to manage flaky tests effectively.This system can help maintain a clean codebase by automatically disabling tests that fail consistently, thereby preventing unnecessary disruptions in the development workflow.
Common Pitfalls
1
Relying on flaky tests can lead to a false sense of security and hinder development.
Flaky tests may pass intermittently, causing developers to overlook real issues, which can result in significant regressions and wasted time fixing unrelated problems.
2
Failing to disable unreliable tests can block the development process.
If tests are not regularly reviewed and disabled when they fail consistently, they can prevent developers from committing new code, leading to frustration and decreased productivity.
Related Concepts
Continuous Integration
Automated Testing
Mock Servers
Testing Frameworks