# 附录 2：Testing Library 组件测试基础

> The more your tests resemble the way your software is used, the more confidence they can give you.

![](https://2897586075-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LquCgGNObzQ8HY5Og1P%2F-M1icsl1439tpJGHvvdT%2F-M1ictY6GSmb3pLO5XTO%2Freact-testing-library-enzyme-comparison.png?generation=1583477923458255\&alt=media)

```javascript
import { render } from '@testing-library/react'

test('should show h1 title', () => {
  // given
  const comp = render(<App />)

  // when
  const result = comp.getByTestId('title').textContent

  // then
  expect(result).toBe('练功房前端脚手架')
})
```

## Query 查找元素

```javascript
getByLabelText
getByPlaceholderText
getByText
getByDisplayValue

getByAltText
getByTitle
getByRole

getByTestId
```

## [Which query should I use?](https://testing-library.com/docs/guide-which-query)

| type           | *No Match* | *1 Match* | *1+ Match* | *Await?* |
| -------------- | ---------- | --------- | ---------- | -------- |
| ***getBy***    | *throw*    | *return*  | *throw*    | *No*     |
| ***findBy***   | *throw*    | *return*  | *throw*    | *Yes*    |
| ***queryBy***  | *null*     | *return*  | *throw*    | *No*     |
| **getAllBy**   | throw      | array     | array      | No       |
| **findAllBy**  | throw      | array     | array      | Yes      |
| **queryAllBy** | \[]        | array     | array      | No       |

## 测试组件的交互行为

```javascript
import { render } from '@testing-library/react'
import userEvent from '@testing-library/user-event'

test('should calculate result by input number', () => {
  const comp = render(<App />)

  userEvent.type(comp.getByTestId('input-number'), '15')

  expect(wrapper.getByTestId('number-result').textContent).toBe('FizzBuzz')
})
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://jimmylv.gitbook.io/tdd-frontend/coding/00-project-fizzbuzz/09-appendix-testing-library-basic.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.