Cypress

Cypress

Cypress is a next generation front end testing tool built for the modern web. It runs inside the browser (unlike Selenium/Playwright) which gives it native access to the DOM.

When to Use

• Dev Experience: The interactive GUI is best-in-class for debugging.
• Component Testing: Testing React/Vue/Angular components in isolation within a real browser.
• Single Tab: Testing flows that happen in a single tab/window.

Quick Start

describe("My First Test", () => {
  it("Visits the Kitchen Sink", () => {
    cy.visit("https://example.cypress.io");
    cy.contains("type").click();
    cy.url().should("include", "/commands/actions");
    cy.get(".action-email")
      .type("fake@email.com")
      .should("have.value", "fake@email.com");
  });
});

Core Concepts

Chaining

Cypress commands run serially. cy.get().click().should() reads like a story.

Automatic Retries

Cypress automatically retries assertions until they pass or timeout. cy.get('.todo-list li').should('have.length', 2) will retry until the list has 2 items or 4 seconds elapse.

Stubbing

Because it runs in-browser, intercepting network requests (cy.intercept) is fast and reliable.

Best Practices (2025)

Do:

• Use cy.intercept: Wait for network calls to finish before asserting UI. cy.wait('@apiCall').
• Use Custom Commands: Extract repetitive logic (login) into cy.login().
• Use Data Test Attributes: data-cy="submit-btn" allows you to change CSS/JS without breaking tests.

Don't:

• Don't use wait(number): Never hard-code waits. Wait for routes or elements.
• Don't test 3rd party sites: Cypress is for your app. It has safeguards that make testing Google/Github hard.

References

• Cypress Documentation