driver-pattern

Driver Pattern

A project for generating react test drivers.

Features:

• Automatic react component property setters
• Automatic redux state setters
• Easily declare getters
• Easily declare actions (including async actions)
• Define the driver once in the top of the test suite and initialize it between tests
• Default component property and state property initializers (initialized for each test)

Resources: BDD feat. Driver & Builder Patterns

Usage

You can see usage examples in the test file, those are some cherry-picked exmaples:

Givens & Getters

Automatically created "givens" based on properties & declared getters:

const NameComponent: FC<ComponentProps> = ({ name }: { name: string }) => (
  <span data-testid="test-name">{name}</span>
);

const driver = createDriver(NameComponent, {
  getters: {
    name: "test-name",
  },
});

driver.given.name("Some Name").when.render();
expect(driver.get.name()!.innerHTML).toEqual("Some Name");

Actions

Actions are defined as a function which receives a get parameter, giving you access to the the get object infered from getters. Simply put, you can use driver.get.someGetter() when performing actions:

When defining actions, you can then use the .on property to trigger them:

const driver = createDriver(Component, {
  getters: {
    button: "test-button",
  },
  actions: get => ({
    click: () => fireEvent.click(driver.get.button()!),
  }),
});
const onClickSpy = jest.fn();
driver.given.onClick(onClickSpy).when.render().on.click();
expect(onClickSpy).toHaveBeenCalledTimes(1);

Async Actions

const driver = createDriver(Component, {
  getters: {
    button: "test-button",
  },
  actions: get => ({
    click: () => {
      fireEvent.click(driver.get.button()!);
      return waitFor(/* some condition */);
    },
  }),
});
await driver.given.onClick(onClickSpy).when.render().on.click();
expect(/* some expectation */);

Default Props

const name = chance.word();
const driver = createDriver(Component, {
  defaultProps: () => ({ name }),
  getters: {
    name: "test-name",
  },
});
driver.when.render();
expect(driver.get.name()!.innerHTML).toEqual(name);

Supprt for redux state

Receives a createStore method, which:

• returns a redux Store (enabling to infer the store state)
• receives a preloadedState state, enabling the driver to inject an initial state

const createStore = ({ preloadedState }: { preloadedState: any }) => configureStore(...);

const driver = createDriver(ReduxComponent, {
  getters: {
    title: "test-redux-title",
  },
  createStore,
});
driver.givenState.title("Some Title").when.render();
expect(driver.get.title()!.innerHTML).toEqual("Some Title");

Default State

it("should get default state from defaultState", () => {
  const title = chance.word();
  const driver = createDriver(ReduxComponent, {
    getters: {
      title: "test-redux-title",
    },
    createStore,
    defaultState: () => ({ title }),
  });
  driver.when.render();
  expect(driver.get.title()!.innerHTML).toEqual(title);
});

Initialize

You can call initialize to empty props & state between tests (or initialize then to defaultProps & defaultState)

describe("test suite", () => {
  const driver = createDriver(Component, {
    getters: {
      propRender: "some-component-prop",
      stateRender: "some-state-prop",
    },
    defaultProps: () => ({
      someComponentProp: chance.string()
    }),
    createStore,
    defaultProps: () => ({
      someStateProp: chance.string()
    }),
  });

  // The following will initialize both props & state using the generate methods provided
  // in the creation method above.
  // In the following tests, the values for driver.get.propRender() & driver.get.stateRender()
  // will be populated, and regenerated in each test anew.
  beforeEach(() => driver.initialize());

  it("test 1", () => {
    // ...
  });

  it("test 2", () => {
    // ...
  });
});