In this article, we will analyze the causes of flaky Cypress tests, explore debugging techniques, and provide best practices to ensure stable and reliable test execution.

Understanding Flaky Tests in Cypress

Flaky tests are tests that produce different results across multiple runs without changes to the application. Common causes include:

• Elements not being available before Cypress interacts with them.
• Animations or CSS transitions affecting test stability.
• Asynchronous API calls delaying UI updates.
• Race conditions where test execution outpaces application rendering.
• Incorrect handling of network stubbing and response delays.

Common Symptoms

• Tests passing locally but failing in CI/CD pipelines.
• Intermittent test failures on the same test case.
• Errors like “Timed out retrying after 4000ms” for missing elements.
• UI elements appearing after Cypress attempts to interact with them.
• Unstable assertions due to delayed data fetching.

Diagnosing Flaky Tests in Cypress

1. Using Cypress Retry-Ability

Check whether Cypress is retrying element selection correctly:

cy.get(".button").should("be.visible");

2. Analyzing Network Requests

Ensure API responses arrive before assertions:

cy.intercept("GET", "/api/data", { fixture: "data.json" }).as("getData");
cy.wait("@getData");

3. Debugging with Cypress Logs

Use cy.log() to trace test execution:

cy.log("Checking if button exists");

4. Handling Dynamic Elements

Ensure elements exist before interacting:

cy.get(".loader").should("not.exist");

5. Checking Test Execution Speed

Use cy.wait() for controlled execution:

cy.wait(500);

Fixing Flaky Cypress Tests

Solution 1: Using should() for Assertions

Ensure elements are available before interaction:

cy.get("#submit-button").should("be.visible").click();

Solution 2: Leveraging cy.intercept() for Network Stability

Mock API responses to prevent flakiness:

cy.intercept("GET", "/api/user", { fixture: "user.json" }).as("getUser");
cy.wait("@getUser");

Solution 3: Handling Animation and Transitions

Disable animations during testing:

cy.get(".modal").should("have.css", "opacity", "1");

Solution 4: Implementing Test Retries

Enable retries for unstable tests:

{ "retries": 2 }

Solution 5: Using then() for Asynchronous Behavior

Ensure actions execute sequentially:

cy.get("#username").then(($el) => {
  cy.wrap($el).type("testuser");
});

Best Practices for Stable Cypress Tests

• Use cy.should() for assertions instead of hard waits.
• Mock API responses to eliminate network inconsistencies.
• Ensure elements are fully loaded before interacting.
• Use Cypress test retries to handle occasional failures.
• Log debugging information to track execution flow.

Conclusion

Flaky Cypress tests can lead to unreliable automation results and wasted debugging time. By ensuring proper element availability, stabilizing API responses, and managing animations effectively, developers can create robust and consistent end-to-end tests.

FAQ

1. Why do my Cypress tests fail intermittently?

Tests may fail due to delayed element rendering, asynchronous data fetching, or animations affecting visibility.

2. How do I prevent Cypress from clicking elements too early?

Use cy.should("be.visible") before interacting with elements.

3. What is the best way to handle API response delays?

Use cy.intercept() and cy.wait() to control request timing.

4. Can Cypress automatically retry failing tests?

Yes, enable test retries in cypress.json or individual test configurations.

5. How do I debug Cypress tests efficiently?

Use cy.log() and cy.screenshot() to track test execution flow.