go test加参数-json就能输出 json格式，下面我们用一个简单的例子看下对他进行分析，然后分析下相关源码。对于单测
代码语言：javascript复制package test
import (
"fmt"
"testing"
)
func TestAdd(t *testing.T) {
type args struct {
a int
b int
}
tests := []struct {
name string
args args
want int
}{
// TODO: Add test cases.
{
args: args{
a: 1,
b: 2,
},
want: 3,
},
{
args: args{
a: 1,
b: 2,
},
want: 4,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := Add(tt.args.a, tt.args.b); got != tt.want {
t.Errorf("Add() = %v, want %v", got, tt.want)
}
})
}
}
func TestSub(t *testing.T) {
type args struct {
a int
b int
}
tests := []struct {
name string
args args
want int
}{
// TODO: Add test cases.
{
args: args{
a: 1,
b: 2,
},
want: -1,
},
}
for _, tt := range tests {
fmt.Println("before")
fmt.Print("before not endline")
t.Run(tt.name, func(t *testing.T) {
if got := Sub(tt.args.a, tt.args.b); got != tt.want {
t.Errorf("Sub() = %v, want %v", got, tt.want)
}
})
fmt.Println("after")
t.Skip("skipping test; 1 not set")
}
}执行命令
代码语言：javascript复制% go test ./test/gotest/test/... -json它的输出如下：
代码语言：javascript复制{"Time":"2023-05-13T17:27:15.492681 08:00","Action":"run","Package":"learn/test/gotest/test","Test":"TestAdd"}
{"Time":"2023-05-13T17:27:15.493129 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd","Output":"=== RUN TestAddn"}
{"Time":"2023-05-13T17:27:15.49316 08:00","Action":"run","Package":"learn/test/gotest/test","Test":"TestAdd/#00"}
{"Time":"2023-05-13T17:27:15.493168 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd/#00","Output":"=== RUN TestAdd/#00n"}
{"Time":"2023-05-13T17:27:15.493185 08:00","Action":"run","Package":"learn/test/gotest/test","Test":"TestAdd/#01"}
{"Time":"2023-05-13T17:27:15.493191 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd/#01","Output":"=== RUN TestAdd/#01n"}
{"Time":"2023-05-13T17:27:15.493195 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd/#01","Output":" add_test.go:38: Add() = 3, want 4n"}
{"Time":"2023-05-13T17:27:15.493444 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd","Output":"--- FAIL: TestAdd (0.00s)n"}
{"Time":"2023-05-13T17:27:15.493471 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd/#00","Output":" --- PASS: TestAdd/#00 (0.00s)n"}
{"Time":"2023-05-13T17:27:15.493477 08:00","Action":"pass","Package":"learn/test/gotest/test","Test":"TestAdd/#00","Elapsed":0}
{"Time":"2023-05-13T17:27:15.49349 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestAdd/#01","Output":" --- FAIL: TestAdd/#01 (0.00s)n"}
{"Time":"2023-05-13T17:27:15.493495 08:00","Action":"fail","Package":"learn/test/gotest/test","Test":"TestAdd/#01","Elapsed":0}
{"Time":"2023-05-13T17:27:15.493499 08:00","Action":"fail","Package":"learn/test/gotest/test","Test":"TestAdd","Elapsed":0}
{"Time":"2023-05-13T17:27:15.493503 08:00","Action":"run","Package":"learn/test/gotest/test","Test":"TestSub"}
{"Time":"2023-05-13T17:27:15.493506 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"=== RUN TestSubn"}
{"Time":"2023-05-13T17:27:15.49362 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"beforen"}
{"Time":"2023-05-13T17:27:15.493633 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"before not endline=== RUN TestSub/#00n"}
{"Time":"2023-05-13T17:27:15.493642 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"aftern"}
{"Time":"2023-05-13T17:27:15.493646 08:00","Action":"cont","Package":"learn/test/gotest/test","Test":"TestSub"}
{"Time":"2023-05-13T17:27:15.49365 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"=== CONT TestSubn"}
{"Time":"2023-05-13T17:27:15.493654 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":" add_test.go:72: skipping test; 1 not setn"}
{"Time":"2023-05-13T17:27:15.493659 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub","Output":"--- SKIP: TestSub (0.00s)n"}
{"Time":"2023-05-13T17:27:15.493802 08:00","Action":"output","Package":"learn/test/gotest/test","Test":"TestSub/#00","Output":" --- PASS: TestSub/#00 (0.00s)n"}
{"Time":"2023-05-13T17:27:15.493818 08:00","Action":"pass","Package":"learn/test/gotest/test","Test":"TestSub/#00","Elapsed":0}
{"Time":"2023-05-13T17:27:15.493824 08:00","Action":"skip","Package":"learn/test/gotest/test","Test":"TestSub","Elapsed":0}
{"Time":"2023-05-13T17:27:15.493827 08:00","Action":"output","Package":"learn/test/gotest/test","Output":"FAILn"}
{"Time":"2023-05-13T17:27:15.493899 08:00","Action":"output","Package":"learn/test/gotest/test","Output":"FAILtlearn/test/gotest/testt0.138sn"}
{"Time":"2023-05-13T17:27:15.493915 08:00","Action":"fail","Package":"learn/test/gotest/test","Elapsed":0.139}可以看到，和直直接输出相比，输出格式变成了json，每条输出都是一个json对象，它包含属性有时间，类型、包、测试方法、以及输出等。比不带-json参数多了很多内容
代码语言：javascript复制--- FAIL: TestAdd (0.00s)
--- FAIL: TestAdd/#01 (0.00s)
add_test.go:38: Add() = 3, want 4
before
before not endlineafter
FAIL
FAIL learn/test/gotest/test 0.176s
FAIL下面分析下它的源码实现，源码位于src/cmd/internal/test2json/test2json.go输出被定义成了event类型
代码语言：javascript复制type event struct {
Time *time.Time `json:",omitempty"`
Action string
Package string `json:",omitempty"`
Test string `json:",omitempty"`
Elapsed *float64 `json:",omitempty"`
Output *textBytes `json:",omitempty"`
}其中Converter负责将gotest的输出转化为event事件
代码语言：javascript复制type Converter struct {
w io.Writer // JSON output stream
pkg string // package to name in events
mode Mode // mode bits
start time.Time // time converter started
testName string // name of current test, for output attribution
report []*event // pending test result reports (nested for subtests)
result string // overall test result if seen
input lineBuffer // input buffer
output lineBuffer // output buffer
}构造方法如下
代码语言：javascript复制func NewConverter(w io.Writer, pkg string, mode Mode) *Converter {
c := new(Converter)
*c = Converter{
w: w,
pkg: pkg,
mode: mode,
start: time.Now(),
input: lineBuffer{
b: make([]byte, 0, inBuffer),
line: c.handleInputLine,
part: c.output.write,
},
output: lineBuffer{
b: make([]byte, 0, outBuffer),
line: c.writeOutputEvent,
part: c.writeOutputEvent,
},
}
return c
}退出对应了pass和fail两种action
代码语言：javascript复制func (c *Converter) Exited(err error) {
if err == nil {
c.result = "pass"
} else {
c.result = "fail"
}
}相应的文案定义如下，也就是我们常看到的单测结果
代码语言：javascript复制 updates = [][]byte{
[]byte("=== RUN "),
[]byte("=== PAUSE "),
[]byte("=== CONT "),
}
reports = [][]byte{
[]byte("--- PASS: "),
[]byte("--- FAIL: "),
[]byte("--- SKIP: "),
[]byte("--- BENCH: "),
}根据输入的每一行内容，进行解析，得到event，如果都没有匹配成功，就把前一个测试的名字赋值给当前测试。否则根据冒号截取内容获取Action和Test。最后把原始输入，写入到Output字段里面。
代码语言：javascript复制func (c *Converter) handleInputLine(line []byte) {
// Final PASS or FAIL.
if bytes.Equal(line, bigPass) || bytes.Equal(line, bigFail) || bytes.HasPrefix(line, bigFailErrorPrefix) {
c.flushReport(0)
c.output.write(line)
if bytes.Equal(line, bigPass) {
c.result = "pass"
} else {
c.result = "fail"
}
return
}
if bytes.HasPrefix(line, skipLinePrefix) && bytes.HasSuffix(line, skipLineSuffix) && len(c.report) == 0 {
c.result = "skip"
}
for _, magic := range reports {
if bytes.HasPrefix(line, magic) {
actionColon = true
ok = true
break
}
}
if indent > 0 && indent <= len(c.report) {
c.testName = c.report[indent-1].Test
}
action := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(string(line[4:i])), ":"))
name := strings.TrimSpace(string(line[i:]))
c.output.write(origLine)大于当前层级的结果输出
代码语言：javascript复制func (c *Converter) flushReport(depth int) {
c.testName = ""
for len(c.report) > depth {
e := c.report[len(c.report)-1]
c.report = c.report[:len(c.report)-1]
c.writeEvent(e)
}
}输出output是一个单独的事件
代码语言：javascript复制func (c *Converter) writeOutputEvent(out []byte) {
c.writeEvent(&event{
Action: "output",
Output: (*textBytes)(&out),
})
}最后来到了writevent函数，把包名字和测试名字赋值，然后序列化。加入换行然后输出。
代码语言：javascript复制func (c *Converter) writeEvent(e *event) {
e.Package = c.pkg
if c.mode&Timestamp != 0 {
t := time.Now()
e.Time = &t
}
if e.Test == "" {
e.Test = c.testName
}
js, err := json.Marshal(e)
js = append(js, 'n')
c.w.Write(js)
总的来说，就是解析字符串，转化成json的一个过程。
