我在通过此测试时遇到问题。问题是，Write()我的结构体中的方法需要写入属性，但io.Writer接口不接受指针作为其接收者。

filelogger.go:

package logger

import (
    "io"
)

type FileLogger struct{
    File io.Writer
}

func NewFileLogger(file io.Writer) *FileLogger{
    return &FileLogger{file}
}

func (this *FileLogger) Log(message string) error {
    _, err := this.File.Write([]byte(appendNewLine(message)))

    return err
}

filelogger_test.go:

package logger

import (
    "testing"

    "github.com/stretchr/testify/assert"
)

type WriterMock struct{
    data []byte
}

func (this WriterMock) Write(b []byte) (n int, err error) {
    this.data = append(this.data, b ...)

    return len(this.data), nil
}

func NewMockedFileLogger() *FileLogger{
    writer := WriterMock{}

    fileLogger := FileLogger{writer}

    return &fileLogger
}

func TestLog(t *testing.T) {
    fileLogger := NewMockedFileLogger()

    fileLogger.Log("Hello World!")

    assert.Equal(t, "Hello World!", string(fileLogger.File.(WriterMock).data))
}

测试输出：

--- FAIL: TestLog (0.00 seconds)
        Location:       filelogger_test.go:32
    Error:      Not equal: "Hello World!" (expected)
                    != "" (actual)

FAIL

正如我提到的，data []byte不会被写入，因为我无法将函数接收器设置为指针，因为它不能满足io.Writer。