使用go-beautiful-html-coverage跟踪PR代码覆盖率

go-beautiful-html-coverage是一个用于在Go项目中生成精美HTML覆盖率报告的插件，特别适合在Pull Request中展示代码覆盖率变化。

安装和使用

首先安装插件：

go install github.com/kelveny/go-beautiful-html-coverage@latest

基本用法

1. 首先运行测试并生成覆盖率profile文件：

go test -coverprofile=coverage.out ./...

1. 然后使用插件生成HTML报告：

go-beautiful-html-coverage -coverprofile coverage.out -o coverage.html

在CI/CD中集成

以下是一个GitHub Actions工作流示例，用于在PR中生成和显示覆盖率报告：

name: Test and Coverage

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    
    - name: Set up Go
      uses: actions/setup-go@v2
      with:
        go-version: '1.20'
    
    - name: Run tests with coverage
      run: |
        go test -coverprofile=coverage.out ./...
        go tool cover -func=coverage.out
        
    - name: Generate beautiful HTML coverage report
      run: |
        go install github.com/kelveny/go-beautiful-html-coverage@latest
        go-beautiful-html-coverage -coverprofile coverage.out -o coverage.html
        
    - name: Upload coverage report as artifact
      uses: actions/upload-artifact@v2
      with:
        name: coverage-report
        path: coverage.html

高级功能

1. 排除目录：

go-beautiful-html-coverage -coverprofile coverage.out -o coverage.html -exclude-dirs vendor,testdata

1. 设置阈值（如果覆盖率低于阈值则失败）：

go-beautiful-html-coverage -coverprofile coverage.out -o coverage.html -threshold 80

1. 与GitHub Pages集成：

- name: Deploy to GitHub Pages
  if: github.ref == 'refs/heads/main'
  uses: peaceiris/actions-gh-pages@v3
  with:
    github_token: ${{ secrets.GITHUB_TOKEN }}
    publish_dir: ./
    publish_branch: gh-pages
    keep_files: true

报告特点

生成的HTML报告具有以下特点：

• 美观的可视化界面
• 按目录和文件组织的覆盖率数据
• 彩色编码的覆盖率指标
• 点击文件可查看详细的覆盖/未覆盖行
• 支持与历史覆盖率数据对比

示例代码

以下是一个完整的Go测试示例，展示如何获得良好的覆盖率：

// main.go
package main

import "fmt"

func Add(a, b int) int {
    return a + b
}

func Subtract(a, b int) int {
    return a - b
}

func main() {
    fmt.Println("Calculator")
}

// main_test.go
package main

import "testing"

func TestAdd(t *testing.T) {
    tests := []struct {
        name string
        a, b int
        want int
    }{
        {"positive", 2, 3, 5},
        {"negative", -1, -1, -2},
        {"zero", 0, 0, 0},
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            if got := Add(tt.a, tt.b); got != tt.want {
                t.Errorf("Add() = %v, want %v", got, tt.want)
            }
        })
    }
}

func TestSubtract(t *testing.T) {
    tests := []struct {
        name string
        a, b int
        want int
    }{
        {"positive", 5, 3, 2},
        {"negative", -1, -1, 0},
        {"zero", 0, 0, 0},
    }

    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            if got := Subtract(tt.a, tt.b); got != tt.want {
                t.Errorf("Subtract() = %v, want %v", got, tt.want)
            }
        })
    }
}

运行测试并生成报告后，你将得到一个直观的HTML报告，清楚地展示哪些代码被测试覆盖，哪些没有。