Go学习:测试http服务器

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Go学习:测试http服务器

代码

package filelistingimport ("fmt""io/ioutil""net/http""os""strings"
)const prefix = "/list/"type userError stringfunc (e userError) Error() string {return e.Message()
}func (e userError) Message() string {return string(e)
}func HandlerFIleList(writer http.ResponseWriter, request *http.Request) error {if strings.Index(request.URL.Path, prefix) != 0 {return userError(fmt.Sprintf("path %s must start with %s", request.URL.Path, prefix))}path := request.URL.Path[len(prefix):]file, err := os.Open(path)defer file.Close()if err != nil {return err}bytes, err := ioutil.ReadAll(file)if err != nil {return err}writer.Write(bytes)return nil
}

package mainimport ("learngo/errhandling/filelistingserver/filelisting""log""net/http""os"
)type appHandler func(writer http.ResponseWriter, request *http.Request) errortype userError interface {errorMessage() string
}func errWrapper(handler appHandler) func(writer http.ResponseWriter, request *http.Request) {return func(writer http.ResponseWriter, request *http.Request) {defer func() {if r := recover(); r != nil {log.Printf("Panic %v", r)http.Error(writer, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)}}()err := handler(writer, request)code := http.StatusOKif err != nil {log.Printf("Error occurred handling request: %s",err.Error())if userErr, ok := err.(userError); ok {http.Error(writer,userErr.Message(),http.StatusBadRequest)return}switch {case os.IsNotExist(err):code = http.StatusNotFoundcase os.IsPermission(err):code = http.StatusForbiddendefault:code = http.StatusInternalServerError}http.Error(writer, http.StatusText(code), code)}}
}const prefix = "/list/"func main() {http.HandleFunc(prefix, errWrapper(filelisting.HandlerFIleList))err := http.ListenAndServe(":8888", nil)if err != nil {panic(err)}
}

使用假的Request/Response

package mainimport ("errors""fmt""io/ioutil""net/http""net/http/httptest""os""strings""testing"
)type testingUserError stringfunc (e testingUserError) Error() string {return e.Message()
}func (e testingUserError) Message() string {return string(e)
}func errPanic(http.ResponseWriter, *http.Request) error {panic(123)
}func errUserError(http.ResponseWriter, *http.Request) error {return testingUserError("user Error")
}func errNotFound(http.ResponseWriter, *http.Request) error {return os.ErrNotExist
}func errNoPermission(http.ResponseWriter, *http.Request) error {return os.ErrPermission
}func errUnknown(http.ResponseWriter, *http.Request) error {return errors.New("unknown error")
}func noError(writer http.ResponseWriter, request *http.Request) error {fmt.Fprintln(writer, "no error")return nil
}func TestErrWrapper(t *testing.T) {tests := []struct {handler appHandlercode    intmsg     string}{{noError, 200, "no error"},{errUserError,400, "user Error"},{errPanic, 500, "Internal Server Error"},{errNotFound, 404, "Not Found"},{errNoPermission, 403, "Forbidden"},{errUnknown, 500, "Internal Server Error"},}for _, test := range tests {wrapper := errWrapper(test.handler)response := httptest.NewRecorder()request := httptest.NewRequest(http.MethodGet, "", nil)wrapper(response, request)bytes, _ := ioutil.ReadAll(response.Body)body := strings.Trim(string(bytes), "\n")if test.msg != body || response.Code != test.code {t.Errorf("期望值:(%d,%s); 实际值:(%d,%s)", response.Code, body, test.code, test.msg)}}
}

起服务器

package mainimport ("errors""fmt""io/ioutil""net/http""net/http/httptest""os""strings""testing"
)type testingUserError stringfunc (e testingUserError) Error() string {return e.Message()
}func (e testingUserError) Message() string {return string(e)
}func errPanic(http.ResponseWriter, *http.Request) error {panic(123)
}func errUserError(http.ResponseWriter, *http.Request) error {return testingUserError("user Error")
}func errNotFound(http.ResponseWriter, *http.Request) error {return os.ErrNotExist
}func errNoPermission(http.ResponseWriter, *http.Request) error {return os.ErrPermission
}func errUnknown(http.ResponseWriter, *http.Request) error {return errors.New("unknown error")
}func noError(writer http.ResponseWriter, request *http.Request) error {fmt.Fprintln(writer, "no error")return nil
}func TestErrWrapprtInServer(t *testing.T) {tests := []struct {handler appHandlercode    intmsg     string}{{noError, 200, "no error"},{errUserError,400, "user Error"},{errPanic, 500, "Internal Server Error"},{errNotFound, 404, "Not Found"},{errNoPermission, 403, "Forbidden"},{errUnknown, 500, "Internal Server Error"},}for _, test := range tests {wrapper := errWrapper(test.handler)server := httptest.NewServer(http.HandlerFunc(wrapper))response, _ := http.Get(server.URL)bytes, _ := ioutil.ReadAll(response.Body)body := strings.Trim(string(bytes), "\n")if response.StatusCode != test.code || body != test.msg {t.Errorf("期望值(%d,%s); 实际值:(%d,%s)", test.code, test.msg, response.StatusCode, body)}}
}

将重复代码抽取公共函数

package mainimport ("errors""fmt""io/ioutil""net/http""net/http/httptest""os""strings""testing"
)type testingUserError stringfunc (e testingUserError) Error() string {return e.Message()
}func (e testingUserError) Message() string {return string(e)
}func errPanic(http.ResponseWriter, *http.Request) error {panic(123)
}func errUserError(http.ResponseWriter, *http.Request) error {return testingUserError("user Error")
}func errNotFound(http.ResponseWriter, *http.Request) error {return os.ErrNotExist
}func errNoPermission(http.ResponseWriter, *http.Request) error {return os.ErrPermission
}func errUnknown(http.ResponseWriter, *http.Request) error {return errors.New("unknown error")
}func noError(writer http.ResponseWriter, request *http.Request) error {fmt.Fprintln(writer, "no error")return nil
}var tests = []struct {handler appHandlercode    intmsg     string
}{{noError, 200, "no error"},{errUserError,400, "user Error"},{errPanic, 500, "Internal Server Error"},{errNotFound, 404, "Not Found"},{errNoPermission, 403, "Forbidden"},{errUnknown, 500, "Internal Server Error"},
}func TestErrWrapper(t *testing.T) {for _, test := range tests {wrapper := errWrapper(test.handler)response := httptest.NewRecorder()request := httptest.NewRequest(http.MethodGet, "", nil)wrapper(response, request)checkResponse(t, response.Result(), test.code, test.msg)}
}func TestErrWrapprtInServer(t *testing.T) {for _, test := range tests {wrapper := errWrapper(test.handler)server := httptest.NewServer(http.HandlerFunc(wrapper))response, _ := http.Get(server.URL)checkResponse(t, response, test.code, test.msg)}
}func checkResponse(t *testing.T, response *http.Response, expectedCode int, expectedMsg string) {bytes, _ := ioutil.ReadAll(response.Body)body := strings.Trim(string(bytes), "\n")if response.StatusCode != expectedCode || body != expectedMsg {t.Errorf("期望值(%d,%s); 实际值:(%d,%s)", expectedCode, expectedMsg, response.StatusCode, body)}
}

使用假的Request/Response VS 起服务器

• 使用假的Request/Response

  • 速度快
  • 更加像一个单元测试,只是测试一个小的函数

• 起服务器

  • 集成度比较高,测试到的代码的覆盖量比较大
  • 速度慢