mockPromise

mockPromise.ts

/** Create a mock promise whose lifecycle can be controlled */
const mockPromise = (mockFn: jest.Mock) => {
  let resolve: (_: unknown) => void
  let reject: (_?: unknown) => void
  let promise: Promise<unknown>

  mockFn.mockImplementation(() => {
    promise = new Promise((_resolve, _reject) => {
      resolve = _resolve
      reject = _reject
    })
  })

  return {
    async resolve() {
      resolve(null)
      await promise
    },
    async reject() {
      reject(null)
      await promise
    },
  }
}