CLI

Run specific test

• pass a file pattern as the final argument
  • this would match spec/index.spec.js

jest spec/index

• you can also filter tests by test name (not file name)

jest -t testName

Matchers

Match partial objects, arrays, strings

expect(mockFn).toHaveBeenCalledWith(
    expect.objectContaining({
        id: 123,
        name: expect.stringContaining('sofa'),
        model: expect.stringMatching(/A\d{3}/),
        colors: expect.arrayContaining(['red', 'blue']),
    })
)