ink-testing-library

Utilities for testing Ink apps

Install

$ npm install --save-dev ink-testing-library

Usage

import React from 'react';
import {Text} from 'ink';
import {render} from 'ink-testing-library';

const Counter = ({count}) => <Text>Count: {count}</Text>;

const {lastFrame, rerender} = render(<Counter count={0}/>);
lastFrame() === 'Count: 0'; //=> true

rerender(<Counter count={1}/>);
lastFrame() === 'Count: 1'; //=> true

API

render(tree)

tree

Type: ReactElement

React component to render.

render(<MyApp/>);

This function returns an object, which contains the following methods and properties.

lastFrame()

Type: function

Shortcut to stdout.lastFrame.

frames

Type: array

Shortcut to stdout.frames.

rerender(tree)

Type: function

tree

Type: ReactElement

Rerender root component with different props or replace with another component.

const {rerender} = render(<OldApp/>);
rerender(<NewApp/>);

unmount()

Type: function

Unmount current component.

const {unmount} = render(<Test/>);
unmount();

renderHook(hook, options)

Type: function

Arguments:

• hook (function): Hook to render.
• options (object): Options object with the following properties:
  • wrapper (function): Wrapper component to wrap the hook with.

Render a hook with an optional wrapper, and return the hook's return value. Works like react-testing-library's renderHook.

const useCounter = () => {
	const [count, setCount] = React.useState(0);
	return {count, increment: () => setCount(count + 1)};
};

const {result} = renderHook(() => useCounter());

waitFor(condition, timeout, interval)

Type: function Arguments:

• condition (function): Function that throws an error if the condition is not met.
• timeout (number): Timeout in milliseconds.
• interval (number): Interval in milliseconds.

Wait for a condition to be met. Useful for waiting for side effects. The condition can be jest's expect assertion. Works like react-testing-library's waitFor.

await waitFor(() => expect(result.current.count).toBe(1));

stdin

Type: object

write()

Type: function

Write data to current component's stdin stream.

import {useInput, Text} from 'ink';

const Test = () => {
	useInput(input => {
		console.log(input);
		//=> 'hello'
	});

	return …;
};

const {stdin} = render(<Test/>);
stdin.write('hello');

stdout

Type: object

lastFrame()

Type: function

Return the last rendered frame (output) from stdout stream.

const Test = () => <Text>Hello</Text>;

const {stdout} = render(<Test/>);
stdout.lastFrame(); //=> 'Hello'

frames

Type: array

Array of all rendered frames, where the last frame is also the last item in that array.

const Counter = ({count}) => <Text>Count: {count}</Text>;

const {stdout, rerender} = render(<Counter count={0}/>);
rerender(<Counter count={1}/>);

console.log(stdout.frames); //=> ['Count: 0', 'Count: 1']

stderr

Type: object

lastFrame()

Type: function

Same as lastFrame in stdout, but for stderr stream.

frames

Type: array

Same as frames in stdout, but for stderr stream.