jest
Fetch API not available in Jest environment
TypeError.*fetch.*not a function|fetch is not defined.*test
Fixes
- 1.Mock fetch globally: global.fetch = jest.fn()
- 2.Install jest-fetch-mock or msw for comprehensive HTTP mocking
- 3.Use @testing-library's server (msw) for realistic API mocking
jestfetchmocks
Related Errors
jest3 fixes
Jest assertion value mismatch
expect\(received\)\.toBe\(expected\)|Expected.*Received
- •Check expected vs actual values — use .toEqual() for objects instead of .toBe()
- •For floating point, use .toBeCloseTo() instead of exact equality
jest3 fixes
Jest mock function not called as expected
Expected.*mock.*to have been called|not been called|toHaveBeenCalled
- •Verify the mock is injected correctly — check the module path in jest.mock()
- •Ensure the code path that calls the function is actually reached
jest3 fixes
Jest async test timeout
Exceeded timeout.*Async callback|exceeded.*5000.*ms|jest.*timeout
- •Ensure async functions resolve: await the promise or call done()
- •Increase timeout: jest.setTimeout(10000) or third arg to it()