redux-ledger

Tiny redux middleware to run integration tests with thunks!

Install

npm install --save-dev redux-ledger

Usage

Add ledger middleware to your Redux store. Simulate events and dispatch just as you would before. It will intercept and record all actions. Once you are ready, use ledger.resolve() to wait for any pending thunks to complete, then run your assertions.

Note - For accurate results place ledger as the first middleware in the store.

Recording Actions

Every action in the store can be recorded by adding the middleware to the store.

import makeLedger from "redux-ledger";
import { createStore, applyMiddleware } from "redux";
import thunk from "redux-thunk";

const doA = payload => ({ type: "action_a", payload });
const doB = payload => ({ type: "action_b", payload });

// For the purposes of a demo these are defined inline ...
const doAsyncA = payload => dispatch => {
  return Promise.resolve().then(() => {
    dispatch(doA(payload));
  });
};

// ... but let's pretend they are some long running requests, mocked or not
const doAsyncB = payload => dispatch => {
  return Promise.resolve().then(() => {
    dispatch(doB(payload));
  });
};

test("asynchronous actions fired from my App", () => {
  const ledger = makeLedger();
  const store = createStore(
    (state = {}) => state,
    applyMiddleware(ledger, thunk)
  );
  store.dispatch(doA({ foo: "foo" }));
  store.dispatch(doB({ bar: "bar" }));
  // ledger.getActions() to get all actions recorded
  expect(ledger.getActions()).toMatchSnapshot();
});

Complex Example

redux-ledger shines when you want to unit test an entire component connected to a store.

import makeLedger from "redux-ledger";
import { createStore, applyMiddleware } from "redux";
import { Provider } from "react-redux";
import thunk from "redux-thunk";
import { mount } from "enzyme";
// Component to test
import MyAppContainer from "my-app-container";

test("asynchronous actions fired from my App", () => {
  const ledger = makeLedger();
  const store = createStore(reducer, applyMiddleware(ledger, thunk));
  const wrapper = mount(
    <Provider store={store}>
      <MyAppContainer />
    </Provider>
  );

  // Simulate user interaction which will kick off asynchronous actions
  wrapper.find(MyAppContainer).simulate("click");

  return ledger.resolve().then(actions => {
    expect(actions).toMatchSnapshot();
  });
});

API

`createLedger()` - Factory

You'll want a new ledger for each new store, as ledgers should be scoped to a single store. Returns a ledger middleware instance.

`ledger` - Instance

The middleware function. Has additional methods on the function object:

// Will wait for any pending promise from actions to finish.
// Resolves with the array of actions dispatched
ledger.resolve().then(actions => { ... });

// Will return all actions recorded so far
ledger.getActions(); // [ { type: 'a', ...}, {type: 'b', ...} ]

// Will clear any previously recorded actions
ledger.clearActions();

wayfair-archive/redux-ledger