Promises support

[doomsower]

I just tried Sazerac and it looks awesome. Unfortunately, I couldn't make it work for a very common test scenario of mine, which look something like this (I use Jest):

beforeAll(someFunctionThatReturnsPromise);
beforeEach(anotherAsyncFunc);
beforeEach(afterEachAsyncToo);

describe('resovers chain', () => {
  beforeEach(asyncFuncForAGroupOfTests);

  it('should do some async check', async () => {
     const result = await testedAsyncFunc(givenArgs);
     expect(result).toBeDefined();
  });
});

First I tried something like:

const run = someAsyncFunc

test(run, () => {
  given({ days: 1 })
    .assert('something about days', async (r) => {
      expect(r).toHaveProperty('someprop', 7);
    });
});

This failed because assert invoked jest test in sync manner.

beforeAll(someFunctionThatReturnsPromise);
beforeEach(anotherAsyncFunc);
beforeEach(afterEachAsyncToo);

const run = (vars: Variables) => asyncFunc(query, vars);

const promisify = (assertFn: (value: any) => void) => (p: Promise<any>) => p.then(assertFn);

test(run, () => {
  given({ days: 1 })
    .assert('something about days', promisify((r) => {
      expect(r).toHaveProperty('data.lastMeasurements', null);
    }));
})

This worked for some tests, but failed for some others, because global beforeEach didn't fire, I guess. Probably I could promisify beforeEach too and attach it to each given TestCase, but this way all the clarity that sazerac gives to sync test cases will be gone.

I checked sazerac source code and it seems that adding async support will require huge changes. So this is too much for me to make a PR. Besides, I'm only familiar with jest.

So is there any chance you could add Promises support to sazerac?

[prettymuchbryce]

For anyone else who lands here, it looks like jest supports data-driven tests natively now.

http://jestjs.io/docs/en/api#testeachtable-name-fn