API 测试

简介

Playwright 可以用来访问你应用程序的 REST API。

有时你可能想直接从 Node.js 向服务器发送请求，而无需加载页面并在其中运行 js 代码。以下是一些可能派上用场的例子

• 测试你的服务器 API。
• 在测试中访问 Web 应用程序之前，准备服务器端状态。
• 在浏览器中运行一些操作后，验证服务器端后置条件。

所有这些都可以通过 APIRequestContext 方法实现。

编写 API 测试

APIRequestContext 可以通过网络发送各种 HTTP(S) 请求。

以下示例演示了如何使用 Playwright 通过 GitHub API 测试 issue 创建。测试套件将执行以下操作

• 在运行测试之前创建一个新的存储库。
• 创建一些 issue 并验证服务器状态。
• 在运行测试后删除存储库。

配置

GitHub API 需要授权，因此我们将为所有测试配置一次 token。同时，我们还将设置 baseURL 以简化测试。你可以将它们放在配置文件中，或使用 test.use() 放在测试文件中。

playwright.config.ts

import { defineConfig } from '@playwright/test';
export default defineConfig({
  use: {
    // All requests we send go to this API endpoint.
    baseURL: 'https://api.github.com',
    extraHTTPHeaders: {
      // We set this header per GitHub guidelines.
      'Accept': 'application/vnd.github.v3+json',
      // Add authorization token to all requests.
      // Assuming personal access token available in the environment.
      'Authorization': `token ${process.env.API_TOKEN}`,
    },
  }
});

代理配置

如果你的测试需要通过代理运行，你可以在配置中指定它，request fixture 将自动获取它

playwright.config.ts

import { defineConfig } from '@playwright/test';
export default defineConfig({
  use: {
    proxy: {
      server: 'http://my-proxy:8080',
      username: 'user',
      password: 'secret'
    },
  }
});

编写测试

Playwright Test 自带内置的 request fixture，它尊重我们指定的 baseURL 或 extraHTTPHeaders 等配置选项，并准备好发送一些请求。

现在我们可以添加一些将在存储库中创建新 issue 的测试。

const REPO = 'test-repo-1';
const USER = 'github-username';

test('should create a bug report', async ({ request }) => {
  const newIssue = await request.post(`/repos/${USER}/${REPO}/issues`, {
    data: {
      title: '[Bug] report 1',
      body: 'Bug description',
    }
  });
  expect(newIssue.ok()).toBeTruthy();

  const issues = await request.get(`/repos/${USER}/${REPO}/issues`);
  expect(issues.ok()).toBeTruthy();
  expect(await issues.json()).toContainEqual(expect.objectContaining({
    title: '[Bug] report 1',
    body: 'Bug description'
  }));
});

test('should create a feature request', async ({ request }) => {
  const newIssue = await request.post(`/repos/${USER}/${REPO}/issues`, {
    data: {
      title: '[Feature] request 1',
      body: 'Feature description',
    }
  });
  expect(newIssue.ok()).toBeTruthy();

  const issues = await request.get(`/repos/${USER}/${REPO}/issues`);
  expect(issues.ok()).toBeTruthy();
  expect(await issues.json()).toContainEqual(expect.objectContaining({
    title: '[Feature] request 1',
    body: 'Feature description'
  }));
});

设置和清理

这些测试假设存储库存在。你可能需要在运行测试之前创建一个新的存储库，并在之后删除它。为此使用 beforeAll 和 afterAll hook。

test.beforeAll(async ({ request }) => {
  // Create a new repository
  const response = await request.post('/user/repos', {
    data: {
      name: REPO
    }
  });
  expect(response.ok()).toBeTruthy();
});

test.afterAll(async ({ request }) => {
  // Delete the repository
  const response = await request.delete(`/repos/${USER}/${REPO}`);
  expect(response.ok()).toBeTruthy();
});

使用请求上下文

在幕后，request fixture 实际上会调用 apiRequest.newContext()。如果你想要更多控制权，你可以随时手动执行此操作。下面是一个独立的脚本，它执行与上面 beforeAll 和 afterAll 相同的操作。

import { request } from '@playwright/test';
const REPO = 'test-repo-1';
const USER = 'github-username';

(async () => {
  // Create a context that will issue http requests.
  const context = await request.newContext({
    baseURL: 'https://api.github.com',
  });

  // Create a repository.
  await context.post('/user/repos', {
    headers: {
      'Accept': 'application/vnd.github.v3+json',
      // Add GitHub personal access token.
      'Authorization': `token ${process.env.API_TOKEN}`,
    },
    data: {
      name: REPO
    }
  });

  // Delete a repository.
  await context.delete(`/repos/${USER}/${REPO}`, {
    headers: {
      'Accept': 'application/vnd.github.v3+json',
      // Add GitHub personal access token.
      'Authorization': `token ${process.env.API_TOKEN}`,
    }
  });
})();

从 UI 测试发送 API 请求

在浏览器中运行测试时，你可能希望调用应用程序的 HTTP API。如果你需要在运行测试之前准备服务器状态，或在浏览器中执行某些操作后检查服务器上的一些后置条件，这可能会很有帮助。所有这些都可以通过 APIRequestContext 方法实现。

建立前提条件

以下测试通过 API 创建一个新的 issue，然后导航到项目中的所有 issue 列表，以检查它是否出现在列表顶部。

import { test, expect } from '@playwright/test';

const REPO = 'test-repo-1';
const USER = 'github-username';

// Request context is reused by all tests in the file.
let apiContext;

test.beforeAll(async ({ playwright }) => {
  apiContext = await playwright.request.newContext({
    // All requests we send go to this API endpoint.
    baseURL: 'https://api.github.com',
    extraHTTPHeaders: {
      // We set this header per GitHub guidelines.
      'Accept': 'application/vnd.github.v3+json',
      // Add authorization token to all requests.
      // Assuming personal access token available in the environment.
      'Authorization': `token ${process.env.API_TOKEN}`,
    },
  });
});

test.afterAll(async ({ }) => {
  // Dispose all responses.
  await apiContext.dispose();
});

test('last created issue should be first in the list', async ({ page }) => {
  const newIssue = await apiContext.post(`/repos/${USER}/${REPO}/issues`, {
    data: {
      title: '[Feature] request 1',
    }
  });
  expect(newIssue.ok()).toBeTruthy();

  await page.goto(`https://github.com/${USER}/${REPO}/issues`);
  const firstIssue = page.locator(`a[data-hovercard-type='issue']`).first();
  await expect(firstIssue).toHaveText('[Feature] request 1');
});

验证后置条件

以下测试通过浏览器中的用户界面创建一个新的 issue，然后使用 API 检查它是否已创建

import { test, expect } from '@playwright/test';

const REPO = 'test-repo-1';
const USER = 'github-username';

// Request context is reused by all tests in the file.
let apiContext;

test.beforeAll(async ({ playwright }) => {
  apiContext = await playwright.request.newContext({
    // All requests we send go to this API endpoint.
    baseURL: 'https://api.github.com',
    extraHTTPHeaders: {
      // We set this header per GitHub guidelines.
      'Accept': 'application/vnd.github.v3+json',
      // Add authorization token to all requests.
      // Assuming personal access token available in the environment.
      'Authorization': `token ${process.env.API_TOKEN}`,
    },
  });
});

test.afterAll(async ({ }) => {
  // Dispose all responses.
  await apiContext.dispose();
});

test('last created issue should be on the server', async ({ page }) => {
  await page.goto(`https://github.com/${USER}/${REPO}/issues`);
  await page.getByText('New Issue').click();
  await page.getByRole('textbox', { name: 'Title' }).fill('Bug report 1');
  await page.getByRole('textbox', { name: 'Comment body' }).fill('Bug description');
  await page.getByText('Submit new issue').click();
  const issueId = page.url().substr(page.url().lastIndexOf('/'));

  const newIssue = await apiContext.get(
      `https://api.github.com/repos/${USER}/${REPO}/issues/${issueId}`
  );
  expect(newIssue.ok()).toBeTruthy();
  expect(newIssue.json()).toEqual(expect.objectContaining({
    title: 'Bug report 1'
  }));
});

重用身份验证状态

Web 应用程序使用基于 cookie 或 token 的身份验证，其中身份验证状态存储为 cookies。Playwright 提供了 apiRequestContext.storageState() 方法，该方法可用于从已身份验证的上下文中检索存储状态，然后使用该状态创建新的上下文。

存储状态在 BrowserContext 和 APIRequestContext 之间是可互换的。你可以使用它通过 API 调用登录，然后创建一个新的上下文，其中已经有 cookie。以下代码片段从已身份验证的 APIRequestContext 检索状态，并使用该状态创建一个新的 BrowserContext。

const requestContext = await request.newContext({
  httpCredentials: {
    username: 'user',
    password: 'passwd'
  }
});
await requestContext.get(`https://api.example.com/login`);
// Save storage state into the file.
await requestContext.storageState({ path: 'state.json' });

// Create a new context with the saved storage state.
const context = await browser.newContext({ storageState: 'state.json' });

上下文请求与全局请求

有两种类型的 APIRequestContext

• 与 BrowserContext 关联
• 独立的实例，通过 apiRequest.newContext() 创建

主要区别在于通过 browserContext.request 和 page.request 访问的 APIRequestContext 将从浏览器上下文中填充请求的 Cookie 标头，并且如果 APIResponse 具有 Set-Cookie 标头，则会自动更新浏览器 cookie

test('context request will share cookie storage with its browser context', async ({
  page,
  context,
}) => {
  await context.route('https://www.github.com/', async route => {
    // Send an API request that shares cookie storage with the browser context.
    const response = await context.request.fetch(route.request());
    const responseHeaders = response.headers();

    // The response will have 'Set-Cookie' header.
    const responseCookies = new Map(responseHeaders['set-cookie']
        .split('\n')
        .map(c => c.split(';', 2)[0].split('=')));
    // The response will have 3 cookies in 'Set-Cookie' header.
    expect(responseCookies.size).toBe(3);
    const contextCookies = await context.cookies();
    // The browser context will already contain all the cookies from the API response.
    expect(new Map(contextCookies.map(({ name, value }) =>
      [name, value])
    )).toEqual(responseCookies);

    await route.fulfill({
      response,
      headers: { ...responseHeaders, foo: 'bar' },
    });
  });
  await page.goto('https://www.github.com/');
});

如果你不希望 APIRequestContext 使用和更新来自浏览器上下文的 cookie，你可以手动创建一个新的 APIRequestContext 实例，它将拥有自己的独立 cookie

test('global context request has isolated cookie storage', async ({
  page,
  context,
  browser,
  playwright
}) => {
  // Create a new instance of APIRequestContext with isolated cookie storage.
  const request = await playwright.request.newContext();
  await context.route('https://www.github.com/', async route => {
    const response = await request.fetch(route.request());
    const responseHeaders = response.headers();

    const responseCookies = new Map(responseHeaders['set-cookie']
        .split('\n')
        .map(c => c.split(';', 2)[0].split('=')));
    // The response will have 3 cookies in 'Set-Cookie' header.
    expect(responseCookies.size).toBe(3);
    const contextCookies = await context.cookies();
    // The browser context will not have any cookies from the isolated API request.
    expect(contextCookies.length).toBe(0);

    // Manually export cookie storage.
    const storageState = await request.storageState();
    // Create a new context and initialize it with the cookies from the global request.
    const browserContext2 = await browser.newContext({ storageState });
    const contextCookies2 = await browserContext2.cookies();
    // The new browser context will already contain all the cookies from the API response.
    expect(
        new Map(contextCookies2.map(({ name, value }) => [name, value]))
    ).toEqual(responseCookies);

    await route.fulfill({
      response,
      headers: { ...responseHeaders, foo: 'bar' },
    });
  });
  await page.goto('https://www.github.com/');
  await request.dispose();
});