go 工具链自带代码测试覆盖率：

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$ go test -coverprofile=cover.out ./...
ok      github.com/ymcvalu/leakcheck    2.377s  coverage: 87.8% of statements

会输出代码测试覆盖率，并且生成 cover.out 文件。

...表示路径通配， ./...表示当前目录以及所有子目录，子目录的子目录……。可以通过go help packages查看

go test关于代码测试覆盖率相关的flag：

  • -cover：启用代码覆盖率分析。如果指定了covermode, coverpkg或coverprofile，默认设置cover
  • -covermode：如果设置了-race，默认值为atomic，否则默认为set
    • set： does this statement run?
    • count：how many times does this statement run?
    • atomic：count, but correct in multithreaded tests
  • -coverpkg pattern1,pattern2,pattern3： Apply coverage analysis in each test to packages matching the patterns. The default is for each test to analyze only the package being tested.
  • -coverprofile：Write a coverage profile to the file after all tests have passed.

可以使用go tool cover来分析cover profile。

查看函数的覆盖率：

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$ go tool cover -func=cover.out
github.com/ymcvalu/leakcheck/leakcheck.go:28:   RegisterGoroutineToIgnore       100.0%
github.com/ymcvalu/leakcheck/leakcheck.go:37:   stack                           100.0%
github.com/ymcvalu/leakcheck/leakcheck.go:43:   interestingGoroutines           100.0%
github.com/ymcvalu/leakcheck/leakcheck.go:57:   parseAndFilterGoroutine         76.5%
github.com/ymcvalu/leakcheck/leakcheck.go:90:   bytesToString                   100.0%
github.com/ymcvalu/leakcheck/leakcheck.go:98:   Check                           100.0%
github.com/ymcvalu/leakcheck/leakcheck.go:102:  check                           90.9%
total:                                          (statements)                    87.8%

生成html文件，查看具体的代码测试覆盖情况：

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$ go tool cover -html=cover.out  -o cover.html