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Used Jest to unit-test a React component
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import App from './App'; | |
import React from 'react'; | |
import { configure, shallow } from 'enzyme'; | |
import Adapter from 'enzyme-adapter-react-16'; | |
configure({ adapter: new Adapter() }); | |
describe('App', () => { | |
it('should have the `th` "Todos"', () => { | |
const wrapper = shallow( | |
<App /> | |
); | |
expect( | |
wrapper.contains(<th>Todos</th>) | |
).toBe(true); | |
}); | |
it('should have a `input` element', () => { | |
const wrapper = shallow( | |
<App /> | |
); | |
expect( | |
wrapper.containsMatchingElement( | |
<input /> | |
) | |
).toBe(true); | |
}); | |
it('should have a `button` element', () => { | |
const wrapper = shallow( | |
<App /> | |
); | |
expect( | |
wrapper.containsMatchingElement( | |
<button>Add todo</button> | |
) | |
).toBe(true); | |
}); | |
describe('Input changes', () => { | |
const wrapper = shallow( | |
<App /> | |
); | |
const todo = 'Do the thing'; | |
beforeEach(() => { | |
const input = wrapper.find('input').first(); | |
input.simulate('change', { | |
target: { value: todo } | |
}) | |
}); | |
it('should update the state property `todo`', () => { | |
expect(wrapper.state().todo).toEqual(todo); | |
}); | |
describe('and then submits the form', () => { | |
beforeEach(() => { | |
const form = wrapper.find('form').first(); | |
form.simulate('submit', { | |
preventDefault: () => {}, | |
}); | |
}); | |
it('should add the todo to state', () => { | |
expect(wrapper.state().todos).toContain(todo); | |
}); | |
it('should render the item in the table', () => { | |
expect(wrapper.containsMatchingElement( | |
<td>{todo}</td> | |
)).toBe(true); | |
}); | |
it('should clear the input field', () => { | |
const input = wrapper.find('input').first(); | |
expect(input.props().value).toEqual(''); | |
}); | |
}); | |
}); | |
}); |
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