我是node.js的新手。我正在使用pg和pg-native来为无服务器应用程序在node.js中为PostgreSQL编写代码。我需要为此编写单元测试。我无法使用笑话或sinon模拟pg客户。
我的实际代码是这样的
const { Client } = require('pg');
export const getAlerts = async (event, context) => {
const client = new Client({
user: process.env.DB_USER,
host: process.env.DB_HOST,
database: process.env.DB_DATABASE,
password: process.env.DB_PASSWORD,
port: process.env.PORT
});
await client.connect();
try {
const result = await client.query(`SELECT * FROM public.alerts;`);
console.log(result.rows);
client.end();
return success({ message: `${result.rowCount} item(s) returned`, data: result.rows, status: true });
} catch (e) {
console.error(e.stack);
client.end();
return failure({ message: e, status: false });
}
};
如何在此处模拟pg客户？
答案 0 :(得分：0)
这是使用jestjs的单元测试解决方案：
index.js：
const { Client } = require('pg');
const { success, failure } = require('./handler');
export const getAlerts = async (event, context) => {
const client = new Client({
user: process.env.DB_USER,
host: process.env.DB_HOST,
database: process.env.DB_DATABASE,
password: process.env.DB_PASSWORD,
port: process.env.PORT,
});
await client.connect();
try {
const result = await client.query(`SELECT * FROM public.alerts;`);
console.log(result.rows);
client.end();
return success({ message: `${result.rowCount} item(s) returned`, data: result.rows, status: true });
} catch (e) {
console.error(e.stack);
client.end();
return failure({ message: e, status: false });
}
};
hander.js：
export function success(data) {}
export function failure(data) {}
index.spec.js：
import { getAlerts } from './';
import { Client } from 'pg';
import { success, failure } from './handler';
jest.mock('pg', () => {
const mClient = {
connect: jest.fn(),
query: jest.fn(),
end: jest.fn(),
};
return { Client: jest.fn(() => mClient) };
});
jest.mock('./handler.js', () => {
return {
success: jest.fn(),
failure: jest.fn(),
};
});
describe('59540432', () => {
let client;
beforeEach(() => {
client = new Client();
});
afterEach(() => {
jest.clearAllMocks();
});
it('should success', async () => {
client.query.mockResolvedValueOnce({ rows: [], rowCount: 0 });
await getAlerts();
expect(client.connect).toBeCalledTimes(1);
expect(client.query).toBeCalledWith('SELECT * FROM public.alerts;');
expect(client.end).toBeCalledTimes(1);
expect(success).toBeCalledWith({ message: '0 item(s) returned', data: [], status: true });
});
it('should failure', async () => {
const mError = new Error('dead lock');
client.query.mockRejectedValueOnce(mError);
await getAlerts();
expect(client.connect).toBeCalledTimes(1);
expect(client.query).toBeCalledWith('SELECT * FROM public.alerts;');
expect(client.end).toBeCalledTimes(1);
expect(failure).toBeCalledWith({ message: mError, status: false });
});
});
覆盖率100％的单元测试结果：
PASS src/stackoverflow/59540432/index.spec.js (11.792s)
59540432
✓ should success (16ms)
✓ should failure (5ms)
console.log src/stackoverflow/59540432/index.js:3131
[]
console.error src/stackoverflow/59540432/index.js:3155
Error: dead lock
at /Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:39:20
at step (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:33:23)
at Object.next (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:14:53)
at /Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:8:71
at new Promise (<anonymous>)
at Object.<anonymous>.__awaiter (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:4:12)
at Object.<anonymous> (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/src/stackoverflow/59540432/index.spec.js:38:24)
at Object.asyncJestTest (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/node_modules/jest-jasmine2/build/jasmineAsyncInstall.js:102:37)
at resolve (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/node_modules/jest-jasmine2/build/queueRunner.js:43:12)
at new Promise (<anonymous>)
at mapper (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/node_modules/jest-jasmine2/build/queueRunner.js:26:19)
at promise.then (/Users/ldu020/workspace/github.com/mrdulin/jest-codelab/node_modules/jest-jasmine2/build/queueRunner.js:73:41)
at process._tickCallback (internal/process/next_tick.js:68:7)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.js | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 2 passed, 2 total
Snapshots: 0 total
Time: 14.109s
源代码：https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/59540432
答案 1 :(得分：0)
我不建议任何人使用它，并且可能会出现一些错误，但是目前我已经获得100％的单元测试覆盖率...
它涵盖了带有回调的Pool API，而不是所有人似乎都关注的Client API。
jest.mock('pg')
const { Pool } = require('pg')
const mockPgPoolOn = jest.fn((_event, callback) => { callback() })
const mockPgPoolConnectClientClose = jest.fn(() => {})
const mockPgPoolConnectQueryDoneFn = jest.fn(() => {
mockPgPoolConnectClientClose()
})
let mockPgPoolConnectErr = null
let mockPgPoolConnectQueryErr = null
let mockPgPoolConnectQueryResult = null
const mockPgPoolConnectQuery = jest.fn((_text, _params, callback) => {
callback(
mockPgPoolConnectQueryErr,
mockPgPoolConnectQueryResult
)
})
const mockPgPoolConnectClient = jest.fn(() => {
return {
query: mockPgPoolConnectQuery,
on: mockPgPoolOn,
close: mockPgPoolConnectClientClose
}
})
const mockPgPoolConnect = jest.fn((callback) => {
callback(
mockPgPoolConnectErr,
mockPgPoolConnectClient(),
mockPgPoolConnectQueryDoneFn
)
})
let mockPgPoolQueryErr = null
let mockPgPoolQueryResult = null
const mockPgPoolQuery = jest.fn((_text, _params, callback) => {
callback(mockPgPoolQueryErr, mockPgPoolQueryResult)
})
Pool.mockImplementation((_config) => {
return {
connect: mockPgPoolConnect,
query: mockPgPoolQuery,
on: mockPgPoolOn
}
})
const db = require('./index') // My module that uses require('pg')
我也有需要清理的处理程序，因为这是在我开始定义任何内容之前的全部操作……
afterEach(() => {
mockPgPoolQuery.mockClear()
mockPgPoolConnect.mockClear()
// ...
mockPgPoolQueryErr = null
mockPgPoolConnectErr = null
mockPgPoolConnectQueryErr = null
mockPgPoolConnectQueryResult = null
mockPgPoolQueryResult = null
// ...
})
这似乎是一项艰巨的工作，就像我说过的那样，尽管它使我获得了1：1匹配观察到的用法的报道，但似乎很多。
我正在使用回调API，因为它是pg依赖项记录的内容……到目前为止还不喜欢它。
答案 2 :(得分：0)
这是一个老问题，但这是一个新答案：
您可以看看pg-mem，这是我最近发布的一个库，它模仿内存中的postgres实例。
它支持大多数常见的SQL查询（但在语法不太频繁时会失败-如果遇到这种情况，则会提出问题）。
我写了一篇有关here的文章
有关您的用例，请参见this section