Introduction
In the ever-evolving landscape of software development, ensuring the reliability and robustness of applications is paramount. One of the key strategies to achieve this is through effective test automation, particularly focusing on the concepts of run and repeat. This comprehensive guide explores the intricacies of retries, reruns, and repetitions in test automation, drawing insights from best practices and real-world applications. By mastering these techniques, teams can significantly enhance their testing processes, reduce flakiness, and deliver high-quality software products.
The Importance of Run and Repeat in Test Automation
The modern internet is built on the foundation of retries and redundancy. Software and hardware failures are common, and systems are designed to handle these failures gracefully. In test automation, the concepts of run and repeat are crucial for several reasons:
Enhancing Reliability
By incorporating retries and reruns into test automation, teams can ensure that temporary glitches or network issues do not lead to false negatives. This approach helps in identifying real issues that need attention.
Reducing Flakiness
Flaky tests—those that pass or fail inconsistently—can undermine the confidence in automated test suites. Implementing retries can help mitigate this issue, ensuring that tests are reliable and consistent.
Improving Efficiency
Automated retries and reruns can save significant time and effort by reducing the need for manual intervention. This efficiency is particularly valuable in continuous integration and continuous deployment (CI/CD) pipelines.
Retry: Ensuring Command and Assertion Reliability
Retries are a fundamental aspect of test automation, especially when dealing with asynchronous operations or variable response times. In the context of Cypress Test Runner, retries are built into commands and assertions, ensuring that tests are resilient to temporary issues.
Command Retry-Ability
Cypress’s built-in retry mechanism for commands like cy.get and cy.its ensures that the test script keeps retrying until the assertion passes or the timeout is reached. This feature is crucial for handling scenarios where elements take time to appear or load.
Example:
javascript
it('adds todos', () => {
cy.visit('/')
cy.get('.new-todo').type('write code{enter}')
cy.get('.todo').should('have.length', 1)
})In this example, the command cy.get('.todo').should('have.length', 1) is retried until the assertion passes or times out, ensuring reliability.
Assertion Retry-Ability
Assertions in Cypress also benefit from retries. If an assertion fails initially, Cypress will keep retrying until the condition is met or the timeout occurs. This approach minimizes false negatives due to temporary conditions.
Example:
javascript
cy.get('.todo').should('have.length', 1)The above assertion will keep retrying until the length of elements with class todo is 1, ensuring the test does not fail due to transient issues.
Rerun: Handling Temporary Failures and Flaky Tests
Retries within a single command or assertion might not always be sufficient. Sometimes, tests fail due to temporary issues such as server delays or network hiccups. In such cases, rerunning the entire test can help determine if the failure is consistent or just a fluke.
Implementing Reruns
Cypress introduced Test Retries in version 5, allowing tests to be rerun a specified number of times before being marked as failed. This feature is particularly useful for tests that interact with external services or have variable performance characteristics.
Example:
javascript
it('is faster than 300ms', { retries: 3 }, () => {
cy.visit('index.html')
cy.server()
cy.route('POST', '/posts').as('post')
cy.get('#load').click()
cy.wait('@post').its('duration').should('be.lessThan', 300)
})In this example, the test is rerun up to three times if it fails, ensuring that temporary issues do not cause false negatives.
Benefits of Reruns
Identifying Flaky Tests: By rerunning tests, teams can identify tests that fail intermittently and address the underlying causes.
Improving Test Suite Reliability: Reruns help ensure that the test suite is robust and reliable, reducing the chances of false failures.
Enhancing CI/CD Pipelines: In CI/CD environments, reruns ensure that builds are not halted due to temporary issues, maintaining the flow of development and deployment.
Repeat: Stress Testing and Ensuring Robustness
Repetition in test automation involves running the same test multiple times to ensure its reliability and identify any flakiness. This approach is useful for stress testing and ensuring that tests can handle repeated execution without issues.
Implementing Repetition
Cypress allows for easy repetition of tests using loops or utilities like Lodash. By running tests multiple times, teams can ensure that the tests are consistent and reliable.
Example:
javascript
Cypress._.times(100, (k) => {
it(`typing hello ${k + 1} / 100`, () => {
cy.visit('/')
cy.get('#enter-text').type('hello').should('have.value', 'hello')
})
})In this example, the same test is run 100 times in a row to check for any inconsistencies or flaky behavior.
Benefits of Repetition
Stress Testing: Running tests multiple times helps identify any issues that might arise under repeated execution.
Improving Test Consistency: Repetition ensures that tests are reliable and consistent, reducing the likelihood of flakiness.
Detecting Hidden Issues: By running tests repeatedly, teams can uncover hidden issues that might not be evident in a single execution.
Advanced Techniques for Run and Repeat in Test Automation
Using Cypress-Repeat
Cypress-Repeat is a tool that extends the capabilities of Cypress by allowing entire test runs to be repeated. This is useful for finding flaky tests and ensuring that the test suite is robust.
Example:
bash
npm i -D cypress-repeat
npx cypress-repeat run -n 5 --until-passes --recordThe above command runs the test suite up to five times, ensuring that all tests pass before exiting. If any tests fail, the entire run is repeated until all tests pass or the maximum number of retries is reached.
Dynamic Tests with Cypress-Grep
Cypress-Grep allows for dynamic selection and repetition of tests based on tags or test titles. This flexibility is useful for targeting specific tests or scenarios that need additional scrutiny.
Example:
bash
npx cypress run --env grep="typing hello",burn=100This command repeats tests with the title "typing hello" 100 times, ensuring thorough testing of that specific scenario.
Conclusion
In the world of test automation, the concepts of run and repeat are essential for ensuring the reliability and robustness of test suites. By incorporating retries, reruns, and repetitions, teams can significantly reduce flakiness, improve test reliability, and enhance the overall quality of their software products. Tools like Cypress and its extensions provide powerful capabilities to implement these strategies effectively, helping teams deliver high-quality software with confidence.
Key Takeaways
Retries: Essential for handling transient issues and improving command and assertion reliability.
Reruns: Useful for addressing temporary failures and reducing flakiness in tests.
Repetition: Important for stress testing and ensuring test consistency and reliability.
Tools: Cypress, Cypress-Repeat, and Cypress-Grep provide powerful capabilities for implementing run and repeat strategies.
Efficiency: Automated retries and reruns save time and effort, enhancing CI/CD pipeline efficiency.
FAQs
What is the importance of retries in test automation?
Retries help ensure that temporary issues do not lead to false negatives in test results. By retrying commands and assertions, tests can handle transient conditions and improve reliability.
How do reruns differ from retries?
Retries focus on repeating individual commands or assertions within a test, while reruns involve executing the entire test again. Reruns are useful for handling temporary failures or flaky tests.
Why is repetition important in test automation?
Repetition helps identify flaky tests and ensures that tests are reliable and consistent under repeated execution. It is also useful for stress testing and uncovering hidden issues.
How does Cypress handle retries and reruns?
Cypress has built-in support for retries within commands and assertions. Additionally, Cypress v5 introduced Test Retries, allowing tests to be rerun a specified number of times.
What is Cypress-Repeat?
Cypress-Repeat is a tool that extends Cypress by allowing entire test runs to be repeated. It is useful for finding flaky tests and ensuring the robustness of the test suite.
How can Cypress-Grep be used in test automation?
Cypress-Grep allows for dynamic selection and repetition of tests based on tags or test titles. It provides flexibility in targeting specific tests for additional scrutiny.
What are the benefits of using visual AI in test automation?
Visual AI helps automate the comparison of UI elements, identifying differences in layout, color, contrast, and content. This enhances the accuracy and efficiency of test automation.
How can teams improve test suite reliability?
Teams can improve test suite reliability by incorporating retries, reruns, and repetitions, using tools like Cypress and its extensions to handle transient issues and ensure consistent test results.
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