Test dispatch

dispatch.test.js

import { makeDispatcher } from "../src/redux/store/dispatch.js";
import assert from "assert";

describe("dispatch.js", () => {
   describe("makeDispatcher", () => {
      it("generates a function from state handlers, a reducer and a callback", () => {
          const stateHandlers = {
            getState() {},
            setState(arg) {},
          };
          const onDispatch = () => {};
          const reducer = () => {};

          const dispatcher = makeDispatcher(stateHandlers, reducer, onDispatch);

          assert.equal(dispatcher.hasOwnProperty("dispatch"), true);
       });

       it("returns the action provided", () => {
          const stateHandlers = {
            getState() {},
            setState(arg) {},
          };
          const onDispatch = () => {};
          const reducer = () => {};
          const action = { type: "FOO", value: "FOO" };

          const { dispatch } = makeDispatcher(
            stateHandlers,
            reducer,
            onDispatch
          );

          const expected = action;
          const actual = dispatch(action);

          assert.equal(actual, expected);
       });

       it("calls setState with the newState", () => {
          const spyOnSetState = { arg: "" };

          const stateHandlers = {
            getState() {
              return { state: "BAR" };
            },
            setState(arg) {
              spyOnSetState.arg = arg;
            },
          };
          const onDispatch = () => {};
          const reducer = (state, action) => action.type + state.state;
          const action = { type: "FOO", value: "FOO" };

          const { dispatch } = makeDispatcher(
            stateHandlers,
            reducer,
            onDispatch
          );
          dispatch(action);

          const expected = "FOOBAR";
          const actual = spyOnSetState.arg;

          assert.equal(actual, expected);
       });

       it("calls onDispatch", () => {
          const spyOnDispatch = { called: false };

          const stateHandlers = {
            getState() {},
            setState(arg) {},
          };
          const onDispatch = () => {
            spyOnDispatch.called = true;
          };
          const reducer = () => {};
          const action = {};

          const { dispatch } = makeDispatcher(
            stateHandlers,
            reducer,
            onDispatch
          );
          dispatch(action);

          const expected = true;
          const actual = spyOnDispatch.called;

          assert.equal(actual, expected);
       });
    });
});