Goメモ-234 (カバレッジの結果をHTMLで出力)(coverprofile, go tool cover)

概要
サンプル
参考情報

概要

よく忘れるので、ここにメモメモ。。。

goでカバレッジを採取した後、それをHTMLで出力するには以下のようにします。

$ go test -coverprofile /path/to/coverage/result ./...

$ go tool cover -html /path/to/coverage/result -o /path/to/html/result

サンプル

Taskfile.yml

version: "3"

tasks:
  default:
    cmds:
      - task: clean
      - task: run
      - task: preview
  clean:
    cmds:
      - rm -f {c.out,c.out.html}
  run:
    cmds:
      - go test -coverprofile c.out .
      - go tool cover -html c.out -o c.out.html
  preview:
    cmds:
      - python3 -m http.server 8888

lib.go

コードに意味は無いです。

package main

func Plus[T ~int](x, y T) T {
    if x == 100 {
        return y
    }

    return x + y
}

lib_test.go

package main

import "testing"

func TestPlus(t *testing.T) {
    // Arrange
    var (
        x        = 1
        y        = 2
        expected = 3
    )

    // Act
    result := Plus(x, y)

    // Assert
    if result != expected {
        t.Errorf("[want] %v\t[got] %v", expected, result)
    }
}

実行結果

gitpod /workspace/try-golang (master) $ task -d examples/singleapp/coverage_html_out/

task: [clean] rm -f {c.out,c.out.html}

task: [run] go test -coverprofile c.out .
ok      github.com/devlights/try-golang/examples/singleapp/coverage_html_out    0.002s  coverage: 66.7% of statements

task: [run] go tool cover -html c.out -o c.out.html

task: [preview] python3 -m http.server 8888
Serving HTTP on 0.0.0.0 port 8888 (http://0.0.0.0:8888/) ...