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Testing Http

go의 http 패키지를 테스트 해보려니 감이 잡히지 않는다. request와 response는 어떻게 생성하며 mocking은 어떻게 해야할까? 구글링 중에 httptest 패키지를 발견하였다. 역시 대단한 사람들이다. 코드는 아래 링크를 참고하였다.
Golang httptest Example go httptest 패키지는 크게 두 가지 형태로 사용할 수 있다. Server와 Client이다.

  • testing Go http server handlers
  • testing Go http clients

Testing HttpServer

package main

import (
    "fmt"
    "log"
    "net/http"
    "net/url"
    "strings"
)

// Req: http://localhost:1234/upper?word=abc
// Res: ABC
func upperCaseHandler(w http.ResponseWriter, r *http.Request) {
    query, err := url.ParseQuery(r.URL.RawQuery)
    if err != nil {
        w.WriteHeader(http.StatusBadRequest)
        fmt.Fprintf(w, "invalid request")
        return
    }
    word := query.Get("word")
    if len(word) == 0 {
        w.WriteHeader(http.StatusBadRequest)
        fmt.Fprintf(w, "missing word")
        return
    }
    w.WriteHeader(http.StatusOK)
    fmt.Fprintf(w, strings.ToUpper(word))
}

func main() {
    http.HandleFunc("/upper", upperCaseHandler)
    log.Fatal(http.ListenAndServe(":1234", nil))
}

package main

import (
    "io/ioutil"
    "net/http"
    "net/http/httptest"
    "testing"
)

func TestUpperCaseHandler(t *testing.T) {
    req := httptest.NewRequest(http.MethodGet, "/upper?word=abc", nil)
    w := httptest.NewRecorder()
    upperCaseHandler(w, req)
    res := w.Result()
    defer res.Body.Close()
    data, err := ioutil.ReadAll(res.Body)
    if err != nil {
        t.Errorf("expected error to be nil got %v", err)
    }
    if string(data) != "ABC" {
        t.Errorf("expected ABC got %v", string(data))
    }
}

func (rw *ResponseRecorder) Result() *http.Response

Testing HttpClient

package main

import (
    "io/ioutil"
    "net/http"

    "github.com/pkg/errors"
)

type Client struct {
    url string
}

func NewClient(url string) Client {
    return Client{url}
}

func (c Client) UpperCase(word string) (string, error) {
    res, err := http.Get(c.url + "/upper?word=" + word)
    if err != nil {
        return "", errors.Wrap(err, "unable to complete Get request")
    }
    defer res.Body.Close()
    out, err := ioutil.ReadAll(res.Body)
    if err != nil {
        return "", errors.Wrap(err, "unable to read response data")
    }

    return string(out), nil
}

func NewServer(handler http.Handler) *Server

package main

import (
    "fmt"
    "net/http"
    "net/http/httptest"
    "strings"
    "testing"
)

func TestClientUpperCase(t *testing.T) {
    expected := "dummy data"
    svr := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, expected)
    }))
    defer svr.Close()
    c := NewClient(svr.URL)
    res, err := c.UpperCase("anything")
    if err != nil {
        t.Errorf("expected err to be nil got %v", err)
    }
    // res: expected\r\n
    // due to the http protocol cleanup response
    res = strings.TrimSpace(res)
    if res != expected {
        t.Errorf("expected res to be %s got %s", expected, res)
    }
}