下面逐一介绍笔者接触过的测试手段。

Package bufconn

概要

Taming Complexity in Server/Client(s) Testing in a CI Tool Using gRPC bufconn | Dilip Tadepalli
内部实现是基于管道(pipe)。因为管道是半双工那么只要两端维持两个管道就可以模拟了全双工通信了。管道的是由pipe struct表示的, 内部维护一个ring buffer作为缓冲区

// DialContext creates an in-memory full-duplex network connection, unblocks Accept by
// providing it the server half of the connection, and returns the client half
// of the connection.  If ctx is Done, returns ctx.Err()
func (l *Listener) DialContext(ctx context.Context) (net.Conn, error) {
	p1, p2 := newPipe(l.sz), newPipe(l.sz)
	select {
	case <-ctx.Done():
		return nil, ctx.Err()
	case <-l.done:
		return nil, errClosed
	case l.ch <- &conn{p1, p2}:
		return &conn{p2, p1}, nil
	}
}

Demo

下面是利用bufconn实现的一个echo服务

package tests

import (
	"bytes"
	"net"
	"testing"
	"tools/bufconn"

	log "github.com/sirupsen/logrus"
)

func echoHandle(conn net.Conn) {
	defer conn.Close()
	buf := bytes.Buffer{}

	for {
		piece := make([]byte, 256)

		n, err := conn.Read(piece)

		piece = piece[:n]

		if err != nil {
			break
		}

		buf.Write(piece)

		n, err = conn.Write(piece)
		if err != nil {
			break
		}

		buf.Next(n)

		log.WithField("count", n).Trace("echo several bytes to client")
	}

	log.Debug("connection closed.")
}

func TestEchoBaseOnBufConn(t *testing.T) {
	kMaxBufferSize := 1024 * 1024
	exitCh := make(chan interface{})

	lis := bufconn.Listen(kMaxBufferSize)
	
	// server 
	go func() {
		defer lis.Close()

		for {
			select {
			case <-exitCh:
				return
			default:
				conn, err := lis.Accept()
				if err != nil {
					log.Warn(err)
				}
				go echoHandle(conn)
			}

		}
	}()

	// client
	cli, _ := lis.Dial()

	kText := "hello"

	buf := bytes.Buffer{}

	piece := make([]byte, 256)

	buf.WriteString(kText)

	for buf.Len() != 0 {
		n, err := cli.Write(buf.Bytes())
		if err != nil {
			log.Debug(err)
			t.Fail()
			break
		}
		buf.Next(n)
	}

	n, err := cli.Read(piece)
	if err != nil {
		log.Debug(err)
		t.Fail()
	}

	piece = piece[:n]

	close(exitCh)

	if string(piece) != kText {
		t.Logf("got a broken string from echo service. expected=%v actual=%v\n", kText, buf.String())
		t.Fail()
	}
}

net.Pipe

net.Pipe是由标准库提供的相比于bufconn在某种程度上使用起来更简洁。如果希望测试单个连接那么用net.Pipe更方便如果希望测试快速转换到实际的生产环境用bufconn更方便。

Demo

只需要将TestEchoBaseOnBufConn略作修改。

func TestEchoBaseOnNetPipe(t *testing.T) {
	exitCh := make(chan interface{})

	cli, serv := net.Pipe()

	go echoHandle(serv)

	kText := "hello"

	buf := bytes.Buffer{}

	piece := make([]byte, 256)

	buf.WriteString(kText)

	for buf.Len() != 0 {
		n, err := cli.Write(buf.Bytes())
		if err != nil {
			log.Debug(err)
			t.Fail()
			break
		}
		buf.Next(n)
	}

	n, err := cli.Read(piece)
	if err != nil {
		log.Debug(err)
		t.Fail()
	}

	piece = piece[:n]

	close(exitCh)

	if string(piece) != kText {
		t.Logf("got a broken string from echo service. expected=%v actual=%v\n", kText, buf.String())
		t.Fail()
	}
}

Package httptest

提供针对于Http的测试模拟官网文档已经挺详细的。

Mocking 🕊

Mock functions in Go

参考链接

How does one test net.Conn in unit tests in Golang?