Function resolveFixtureFunction

packages/runner/src/fixture.ts:499–552

(
  fixtureFn: (
    context: unknown,
    useFn: (arg: unknown) => Promise<void>,
  ) => Promise<void>,
  fixtureName: string,
  context: unknown,
  cleanupFnArray: (() => void | Promise<void>)[],
)

}

async function resolveFixtureFunction(
  fixtureFn: (
    context: unknown,
    useFn: (arg: unknown) => Promise<void>,
  ) => Promise<void>,
  fixtureName: string,
  context: unknown,
  cleanupFnArray: (() => void | Promise<void>)[],
): Promise<unknown> {
  // wait for `use` call to extract fixture value
  const useFnArgPromise = createDefer()
  const stackTraceError
    = FIXTURE_STACK_TRACE_KEY in fixtureFn && fixtureFn[FIXTURE_STACK_TRACE_KEY] instanceof Error
      ? fixtureFn[FIXTURE_STACK_TRACE_KEY]
      : undefined
  let isUseFnArgResolved = false

  const fixtureReturn = fixtureFn(context, async (useFnArg: unknown) => {
    // extract `use` argument
    isUseFnArgResolved = true
    useFnArgPromise.resolve(useFnArg)

    // suspend fixture teardown by holding off `useReturnPromise` resolution until cleanup
    const useReturnPromise = createDefer<void>()
    cleanupFnArray.push(async () => {
      // start teardown by resolving `use` Promise
      useReturnPromise.resolve()
      // wait for finishing teardown
      await fixtureReturn
    })
    await useReturnPromise
  }).then(() => {
    // fixture returned without calling use()
    if (!isUseFnArgResolved) {
      const error = new Error(
        `Fixture "${fixtureName}" returned without calling "use". Make sure to call "use" in every code path of the fixture function.`,
      )
      if (stackTraceError?.stack) {
        error.stack = error.message + stackTraceError.stack.replace(stackTraceError.message, '')
      }
      useFnArgPromise.reject(error)
    }
  }).catch((e: unknown) => {
    // treat fixture setup error as test failure
    if (!isUseFnArgResolved) {
      useFnArgPromise.reject(e)
      return
    }
    // otherwise re-throw to avoid silencing error during cleanup
    throw e
  })

  return useFnArgPromise
}

function resolveDeps(
  usedFixtures: TestFixtureItem[],