我想测试组件是否在渲染函数中渲染。组件被封装在Consumer里面。
const TestComponent = () => (
<div>
<ItemsContext.Consumer>
{(value) => (
<Autos
autoEnabled={value.autoEnabled}
/>
)}
</ItemsContext.Consumer>
</div>
);
我在上层组件中设置了context
const AutosWrapper = () => (
<ItemsContext.Provider value={{ autoEnabled: false, sourcesEnabled: true }}>
<TestComponent/>
</ItemsContext.Provider>
)
我的测试如下:
import ItemsContext from '../ItemsContext';
describe('<TestComponent /> Component render', () => {
let wrapper;
beforeEach(() => {
wrapper = shallow(<TestComponent {...props} />);
});
describe('<TestComponent /> rendering', () => {
test('should render child components in <TestComponent /> component', () => {
const autoContextWrapper = wrapper.find(ItemsContext.Consumer).at(0)
.renderProp('children')();
expect(autoContextWrapper.find(Autos).length).toEqual(1);
});
});
});
但是当我运行这个测试的时候,我出现了以下的错误 -- TypeError: Cannot read property 'autoEnabled' of undefined
我无法理解如何将默认值传递给上下文或对其进行模拟。我尝试了这样一个变体,但没有成功。
ItemsContext.Consumer = jest.fn((props) => props.children({ autoEnabled: false }));
你必须用提供者包装你的组件,这样消费者才能访问上下文。这一点特别有用,因为这使你能够改变上下文,并基于给定的上下文值进行断言。
例子:
import ItemsContext from '../ItemsContext';
describe('<TestComponent /> Component render', () => {
describe('<TestComponent /> rendering', () => {
test('should render child components in <SearchResult /> component', () => {
const wrapper = shallow((
<ItemsContext.Provider value={{ autoEnabled: true, sourcesEnabled: true }}>
<TestComponent />
</ItemsContext.Provider>
));
const autoContextWrapper = wrapper
.find(ItemsContext.Consumer)
.at(0)
.renderProp('children')();
expect(autoContextWrapper.find(Topics).length).toEqual(1);
});
});
});