I have a file, called user-service.go and the corresponding test file, called user-service_test.go. As I try to get complete code coverage, I am struggling to get some of the error conditions to actually happen.
Here is the function: GetOrCreateByAccessToken()
//GetOrCreateByAccessToken gets a user from the database with the given access token
func (s *service) GetOrCreateByAccessToken(aT string, client *Client) (*user.User, fcerr.FCErr) {
var currentUser user.OauthUser
req, err := http.NewRequest("GET", "https://openidconnect.googleapis.com/v1/userinfo?access_token=" aT, nil)
if err != nil {
return nil, fcerr.NewInternalServerError("Error when setting up the network request")
}
response, err := client.httpClient.Do(req)
if err != nil {
fmt.Println("error when getting the userinfo with the access token")
return nil, fcerr.NewInternalServerError("Error when trying to verify user identity")
}
defer response.Body.Close()
contents, err := io.ReadAll(response.Body)
if err != nil {
return nil, fcerr.NewInternalServerError("Error when trying to read response from Google about user identity")
}
The main control I have for my tests is that I can pass in a *Client.
Here is the part of the test case where I'd like to have io.ReadAll throw an error:
h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
//manually return the message google would return on an actual request
w.Write([]byte(googleAPIOKResponse))
})
//Call the testHTTPClient() function defined in the test file to substitute my own HandlerFunc
httpClient, teardown := testHTTPClient(h)
defer teardown()
//Call the real NewClient() from my user-service.go
client := NewClient()
//Substitute the default httpClient for the one I've just set up.
client.httpClient = httpClient
resultingUser, err := userService.GetOrCreateByAccessToken(nU.AccessToken, client)
assert.Nil(t, resultingUser)
assert.NotNil(t, err)
assert.Equal(t, http.StatusInternalServerError, err.Status())
Is there somewhere I can write my own version of the .Do() method which will put something in the response which will cause io.ReadAll to return an error? Or is there a better way to achieve the error with just the pre-baked response text I'm already using?
CodePudding user response:
There is not a way to replace the Do method, but there is a way to accomplish your goal.
Create a round tripper type that returns an arbitrary response body:
type respondWithReader struct{ body io.Reader }
func (rr respondWithReader) RoundTrip(req *http.Request) (*http.Response, error) {
return &http.Response{
Proto: "HTTP/1.0",
ProtoMajor: 1,
Header: make(http.Header),
Close: true,
Body: ioutil.NopCloser(rr.body),
}, nil
}
Create an io.Reader that fails:
var errReadFail = errors.New("blah!")
type failReader int
func (failReader) Read([]byte) (int, error) {
return 0, errReadFail
}
Use the stock client with the transport and reader above:
c := http.Client{Transport: respondWithReader{body: failReader(0)}}
resp, err := c.Get("http://whatever.com")
if err != nil {
t.Error(err)
}
defer resp.Body.Close()
// ReadAll returns errReadFail
_, err = ioutil.ReadAll(resp.Body)
if err != errReadFail {
t.Errorf("got err %v, expect %v", err, errReadFail)
}