In a recent webinar, David Ingraham, a seasoned Senior SDET at Matium and Cypress ambassador, talked about the perplexing issue of test flakiness in software development and testing and provided an in-depth strategy for tackling test flakiness. Below we’ll drive into the comprehensive approach shared during the session.
1. Understanding the Causes
Effective flakiness mitigation starts with a clear understanding of the factors influencing test outcomes. Common culprits include tool misuse, environmental variations, race conditions, data dependencies, test independence, retryability, unpredictable application behavior, and external dependencies. By controlling these variables, reducing flakiness becomes achievable.
2. Recognizing and Handling Test Flake
Identifying flaky tests is crucial. One approach is to execute tests locally multiple times using dot only or by wrapping tests in a for-each loop. Additionally, utilizing pipelines and configuring retries are essential. Analyzing historical patterns to spot trends and categorizing tests based on severity and priority provide additional means to combat flakiness effectively.
3. Leveraging Cypress Cloud Capabilities
Cypress Cloud offers features to manage flakiness. The cloud enabler facilitates experimental retries and demonstrates how to implement retries in the pipeline using a SwiftUI configuration file. It plays a vital role in identifying flakiness, providing test analytics, categorizing flake severity, and seamlessly integrating with other tools for notifications and alerts.
The high-powered Cypress Cloud also furnishes detailed information about flaky tests, including their pass/fail history, aided by the analytics feature. Understanding this history is key to addressing flaky tests effectively.
4. Ensuring Test Reliability
Improving test reliability involves ensuring tests operate independently from one another. Cypress's before and beforeEach hooks are excellent tools for defining shared setups. Additionally, the cloud platform has default settings to enforce test independence. A reliable test suite enhances the efficiency of the development pipeline.
There's also a case for reevaluating the value of persistently flaky tests. If a test consistently produces different results, consider whether it provides valuable insights or merely slows down the development pipeline. Seek assistance if necessary and utilize tools like test replay to document failures. Accountability is crucial in this process, fostering a culture that actively addresses flaky tests.
5. Handling Data Within a Test
When considering data handling within a test, two approaches emerge: random data generation versus controlling data within the test's state. Controlling the test's state is typically the preferred choice, demonstrated using Cypress custom commands.
6. Test Optimization
In addition to the cloud, several tools aid in test optimization. For example, using the Cypress cy.intercept command controls the state of the tested data, eliminating race conditions. Cy.intercept can also wait for API requests to finish before validating the visibility of application components. Explicit waits and increased timeouts address timing issues, and for running single tests, the --spec flag in the Cypress run command proves particularly useful.
7. Working with Flaky Tests
It's essential to recognize that the goal isn't to eliminate flaky tests entirely. Rather, the aim is to make flaky tests visible and segregate them from consistently reliable tests, fostering a comprehensive understanding of the testing state. The ultimate outcome is a reliable, stable test system where flakiness is contained, resulting in a more efficient, trustworthy, and robust testing suite.
8. Fostering Accountability and Awareness
The importance of fostering a culture of accountability within teams is emphasized, encouraging developers to stay informed about software updates and tools. By promoting a culture of awareness and accountability, participants were empowered to proactively address testing challenges and ensure the reliability of testing practices.
In conclusion, implementing these robust strategies to manage flakiness can elevate test reliability and efficiency. Utilizing a combination of Cypress Cloud, meticulous data control, and a thorough understanding of the variables influencing test outcomes equips you to navigate flaky test scenarios with confidence. Remember—the key to handling testing flakiness lies in accountability, accurate recognition, and strategic application of mitigations. Happy testing!
Want to dive deeper? Watch the full webinar in action!