next.js/test/unit/next-server-utils.test.ts

/* eslint-env jest */
import { cleanAmpPath } from 'next/dist/server/utils'

// convenience function so tests can be aligned neatly
// and easy to eyeball
const check = (input, expected) => expect(cleanAmpPath(input)).toBe(expected)

describe('cleanAmpPath', () => {
  it('should leave url unchanged when no apm parameter is present', () =>
    check('/some/path?param=blah', '/some/path?param=blah'))

  it('should handle amp as the only parameter', () =>
    check('/some/path?amp=1', '/some/path'))

  it('should handle amp as the first parameter', () =>
    check('/some/path?amp=1&page=10', '/some/path?page=10'))

  it('should handle amp as the middle parameter', () =>
    check('/some/path?page=10&amp=1&last=here', '/some/path?page=10&last=here'))

  it('should handle amp as the last parameter', () =>
    check('/some/path?page=10&amp=1', '/some/path?page=10'))
})