JSON fixture files in Cypress - Framework Patterns

Framework Mode - JSON fixture files

Folder Structure

cypress/
├── e2e/
│   └── login.cy.js          # Test files
├── fixtures/
│   └── user.json            # JSON fixture files for test data
├── support/
│   ├── commands.js          # Custom commands
│   └── e2e.js               # Global support file
cypress.config.js            # Cypress configuration

Test Framework Layers

• Fixtures Layer: Stores JSON files with test data (e.g., user credentials, form inputs).
• Test Layer: Cypress test files in cypress/e2e/ that load fixture data and run tests.
• Support Layer: Custom commands and reusable utilities to interact with fixtures and tests.
• Configuration Layer: cypress.config.js manages environment settings and test options.

Configuration Patterns

Use cypress.config.js to define base URLs and environment variables.

Example snippet to set environment variables for credentials:

const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    baseUrl: 'https://example.com',
    env: {
      username: 'testuser',
      password: 'testpass'
    }
  }
})

Load JSON fixture files in tests using cy.fixture('user.json') to keep test data separate and reusable.

Test Reporting and CI/CD Integration

• Use Cypress built-in reporters or plugins like mochawesome for detailed HTML reports.
• Integrate Cypress tests in CI/CD pipelines (GitHub Actions, Jenkins) to run tests automatically on code changes.
• Store test reports as artifacts in CI for review.
• Use environment variables in CI to manage sensitive data securely instead of hardcoding in fixtures.

Best Practices

1. Keep fixture files small and focused: One JSON file per data type (e.g., users, products).
2. Do not store sensitive data in fixtures: Use environment variables or secure vaults.
3. Use fixtures to separate test data from test logic: Makes tests easier to read and maintain.
4. Load fixtures asynchronously: Use cy.fixture() with then() to ensure data is ready before test steps.
5. Reuse fixture data across multiple tests: Avoid duplication and keep data consistent.

Self Check

Where in this folder structure would you add a new JSON fixture file for product details used in multiple tests?

Key Result

Use JSON fixture files in the cypress/fixtures folder to separate test data from test code for reusable, maintainable tests.

Practice

1. What is the main purpose of using JSON fixture files in Cypress tests?

easy

A. To store test data separately from test code for easy reuse

B. To write test assertions directly inside the JSON file

C. To configure Cypress plugins and environment variables

D. To define custom commands for Cypress tests

Solution

1. Step 1: Understand fixture file role

   Fixture files hold static data like user info or responses to use in tests.

2. Step 2: Identify purpose in Cypress

   They separate test data from code, making tests cleaner and reusable.

3. Final Answer:

   To store test data separately from test code for easy reuse -> Option A

4. Quick Check:

   Fixture files = test data storage [OK]

Hint: Fixtures hold test data, not code or configs [OK]

Common Mistakes:

• Thinking fixtures contain test logic
• Confusing fixtures with config files
• Using fixtures to write assertions

2. Which of the following is the correct way to load a JSON fixture file named user.json in a Cypress test?

easy

A. cy.getFixture('user.json').then((data) => { /* use data */ })

B. cy.loadFixture('user.json').then((data) => { /* use data */ })

C. cy.fixture('user.json').then((data) => { /* use data */ })

D. cy.readFile('user.json').then((data) => { /* use data */ })

Solution

1. Step 1: Recall Cypress fixture command

   Cypress uses cy.fixture() to load fixture files from the fixtures folder.

2. Step 2: Check method names

   Only cy.fixture() is the correct Cypress command; others do not exist or are incorrect.

3. Final Answer:

   cy.fixture('user.json').then((data) => { /* use data */ }) -> Option C

4. Quick Check:

   Use cy.fixture() to load JSON files [OK]

Hint: Use cy.fixture() to load JSON files in Cypress [OK]

Common Mistakes:

• Using non-existent commands like cy.loadFixture
• Confusing cy.readFile with cy.fixture
• Omitting the .then() to access data

3. Given the fixture file user.json with content:

{"name": "Alice", "age": 30}

What will the following Cypress code print to the console?

cy.fixture('user.json').then((user) => {
  console.log(user.name);
  console.log(user.age + 5);
})

medium

A. "user" and 35

B. "Alice" and 35

C. "Alice" and "35"

D. undefined and NaN

Solution

1. Step 1: Understand fixture data structure

   The JSON has keys "name" with value "Alice" and "age" with value 30 (number).

2. Step 2: Analyze console.log statements

   First logs user.name which is "Alice". Second logs user.age + 5, which is 30 + 5 = 35.

3. Final Answer:

   "Alice" and 35 -> Option B

4. Quick Check:

   Access JSON keys correctly = "Alice" and 35 [OK]

Hint: JSON values keep their types; numbers add normally [OK]

Common Mistakes:

• Treating numbers as strings and concatenating
• Using wrong keys or misspelling
• Expecting undefined from valid fixture keys

4. You wrote this Cypress test code to load a fixture:

cy.fixture('config.json').then((config) => {
  expect(config.timeout).to.equal(5000)
})

But the test fails with TypeError: Cannot read property 'timeout' of undefined. What is the most likely cause?

medium

A. The then callback is missing a parameter

B. The expect syntax is incorrect

C. The fixture file contains invalid JSON syntax

D. The fixture file config.json does not exist or is misnamed

Solution

1. Step 1: Analyze error message

   The error says config is undefined, so config.timeout fails.

2. Step 2: Check fixture loading causes

   If the fixture file is missing or misnamed, cy.fixture() returns undefined, causing this error.

3. Final Answer:

   The fixture file config.json does not exist or is misnamed -> Option D

4. Quick Check:

   Missing fixture file = undefined data [OK]

Hint: Check fixture file name and location first [OK]

Common Mistakes:

• Assuming expect syntax causes undefined error
• Ignoring fixture file path or name typos
• Not validating JSON file existence

5. You have a fixture file users.json containing an array of user objects:

[{"id":1,"name":"Bob"},{"id":2,"name":"Carol"},{"id":3,"name":"Dave"}]

How can you write a Cypress test to check that the user with id 2 has the name "Carol"?

hard

A. cy.fixture('users.json').then(users => { expect(users.find(u => u.id === 2).name).to.equal('Carol') })

B. cy.fixture('users.json').then(users => { expect(users[2].name).to.equal('Carol') })

C. cy.fixture('users.json').then(users => { expect(users.id === 2).to.equal('Carol') })

D. cy.fixture('users.json').then(users => { expect(users.name).to.include('Carol') })

Solution

1. Step 1: Understand fixture data structure

   The fixture is an array of objects, each with id and name.

2. Step 2: Find user with id 2 and check name

   Use find() to get the user object where id === 2, then check its name.

3. Final Answer:

   cy.fixture('users.json').then(users => { expect(users.find(u => u.id === 2).name).to.equal('Carol') }) -> Option A

4. Quick Check:

   Use find() to locate object by id [OK]

Hint: Use array.find() to locate object by property [OK]

Common Mistakes:

• Using wrong array index instead of find()
• Comparing id directly to name
• Accessing properties on the whole array