redux-saga-testing/ava/02.simple-saga.test.ts

A no-brainer way of testing your Sagas

import sagaHelper from "../helper";
import { call, put } from "redux-saga/effects";
import avaTest, { Assertions } from "ava";
import sinon from "sinon";

const api = sinon.spy();
const someAction = () => ({ type: "SOME_ACTION", payload: "foo" });

function* mySaga(): any {
  yield call(api);
  yield put(someAction());
}

const test = sagaHelper(mySaga(), avaTest);

test("should have called the mock API first", (result, t: Assertions) => {
  // Here we test that the generator did run the "call" function, with the "api" as an argument.
  // The api funtion is NOT called.
  t.deepEqual(result, call(api));

  // It's very important to understand that the generator ran the 'call' function,
  // which only describes what it does, and that the API itself is never called.
  // This is what we are testing here: (but you don't need to test that in your own tests)
  t.false(api.called);
});

test("and then trigger an action", (result, t: Assertions) => {
  // We then test that on the next step some action is called
  // Here, obviously, 'someAction' is called but it doesn't have any effect
  // since it only returns an object describing the action
  t.deepEqual(result, put(someAction()));
});

test("and then nothing", (result, t: Assertions) => {
  t.is(result, undefined);
});