go testing 在并行模式下以json格式输出错误的case名称

Question

去版本：1.18.1假设我写了这个测试文件parallel_test.gopackage parallel_json_outputimport (    "fmt"    "testing"    "time")func TestP(t *testing.T) {    t.Run("a", func(t *testing.T) {        t.Parallel()        for i := 0; i < 5; i++ {            time.Sleep(time.Second)            fmt.Println("a", i)        }    })    t.Run("b", func(t *testing.T) {        t.Parallel()        for i := 0; i < 5; i++ {            time.Sleep(time.Second)            fmt.Println("b", i)        }    })}跑步后go test parallel_test.go -v -json，我得到了{"Time":"2022-06-11T02:48:10.3262833+08:00","Action":"run","Package":"command-line-arguments","Test":"TestP"}{"Time":"2022-06-11T02:48:10.3672856+08:00","Action":"output","Package":"command-line-arguments","Test":"TestP","Output":"=== RUN   TestP\n"}{"Time":"2022-06-11T02:48:10.3682857+08:00","Action":"run","Package":"command-line-arguments","Test":"TestP/a"}{"Time":"2022-06-11T02:48:10.3682857+08:00","Action":"output","Package":"command-line-arguments","Test":"TestP/a","Output":"=== RUN   TestP/a\n"}{"Time":"2022-06-11T02:48:10.3692857+08:00","Action":"output","Package":"command-line-arguments","Test":"TestP/a","Output":"=== PAUSE TestP/a\n"}{"Time":"2022-06-11T02:48:10.3702858+08:00","Action":"pause","Package":"command-line-arguments","Test":"TestP/a"}...看看这一行{"Time":"2022-06-11T02:48:11.3352891+08:00","Action":"output","Package":"command-line-arguments","Test":"TestP/b","Output":"a 0\n"}。此输出应按案例TestP/a而不是打印b，但输出在并行测试中弄乱了案例名称。这个问题使报告工具生成错误的 HTML 报告，IDE（如 GoLand）也受到影响，无法正确排序并行输出。我在 Github here中发现了一个问题，但是这个问题似乎已经在 go 1.14.6 中得到修复，但是，它仍然出现在 go 1.18 中。我想知道发生了什么以及如何处理它，非常感谢。

Answer 1

fmt通用包对并发环境中当前执行的测试知之甚少是有道理的。

测试包有自己的Log方法可以正确呈现当前测试：

t.Log("a", i)