Remove username formatting(convert lowercase) while saving

Resolves: #288

Add test case to cover username in mixed case

In github usernmae can be in lowercase and mixed
case. So we need to handle both usernames are
equal on our system,

Remove additional username check logic. it's not required.

api/pkg/service/auth/auth.go

@@ -132,7 +132,7 @@ func (r *request) addUser(ghUser *github.User) (*model.User, error) {
 		if err == gorm.ErrRecordNotFound {
 
 			user.GithubName = ghUser.GetName()
-			user.GithubLogin = strings.ToLower(ghUser.GetLogin())
+			user.GithubLogin = ghUser.GetLogin()
 			user.Type = model.NormalUserType
 			user.AvatarURL = ghUser.GetAvatarURL()
 
@@ -155,8 +155,10 @@ func (r *request) addUser(ghUser *github.User) (*model.User, error) {
 		user.GithubName = ghUser.GetName()
 		user.Type = model.NormalUserType
 	}
-	// For existing user, check if URL is not added
-	if user.AvatarURL == "" {
+
+	// For existing user, check if URL is not added or github-login is incorrect
+	if user.AvatarURL == "" || user.GithubLogin != ghUser.GetLogin() {
+		user.GithubLogin = ghUser.GetLogin()
 		user.AvatarURL = ghUser.GetAvatarURL()
 		if err = r.db.Save(&user).Error; err != nil {
 			r.log.Error(err)

api/pkg/service/auth/auth_test.go

@@ -277,3 +277,63 @@ func TestLogin_UserAddedByConfig(t *testing.T) {
 
 	assert.Equal(t, gock.IsDone(), true)
 }
+
+func TestLogin_UserWitMixedUSerName(t *testing.T) {
+	tc := testutils.Setup(t)
+	testutils.LoadFixtures(t, tc.FixturePath())
+
+	defer gock.Off()
+
+	gock.New("https://github.com").
+		Post("/login/oauth/access_token").
+		Reply(200).
+		JSON(map[string]string{
+			"access_token": "test-token",
+		})
+
+	gock.New("https://api.github.com").
+		Get("/user").
+		Reply(200).
+		JSON(map[string]string{
+			"login":      "conFIG-UsER",
+			"name":       "config-user",
+			"avatar_url": "http://config",
+		})
+
+	// Mocks the time
+	token.Now = testutils.Now
+
+	//get old user id
+	old_user := model.User{}
+	err := tc.DB().Where("github_login = ?", "config-user").First(&old_user).Error
+	assert.NoError(t, err)
+
+	authSvc := New(tc)
+	payload := &auth.AuthenticatePayload{Code: "test-code"}
+	res, err := authSvc.Authenticate(context.Background(), payload)
+	assert.NoError(t, err)
+
+	// validate the github login of user after login
+	ut := &model.User{}
+	err = tc.DB().Where("github_login = ?", "conFIG-UsER").First(ut).Error
+	assert.NoError(t, err)
+	// check shouldn't create no new user due to mixed user name 
+	assert.Equal(t, old_user.ID, ut.ID)
+
+	// expected refresh jwt for user
+	user, refreshToken, err := tc.RefreshTokenForUser("conFIG-UsER")
+	assert.Equal(t, user.GithubLogin, "conFIG-UsER")
+	assert.NoError(t, err)
+
+	accessExpiryTime := testutils.Now().Add(tc.JWTConfig().AccessExpiresIn).Unix()
+	refreshExpiryTime := testutils.Now().Add(tc.JWTConfig().RefreshExpiresIn).Unix()
+
+	assert.Equal(t, tc.JWTConfig().AccessExpiresIn.String(), res.Data.Access.RefreshInterval)
+	assert.Equal(t, accessExpiryTime, res.Data.Access.ExpiresAt)
+
+	assert.Equal(t, refreshToken, res.Data.Refresh.Token)
+	assert.Equal(t, tc.JWTConfig().RefreshExpiresIn.String(), res.Data.Refresh.RefreshInterval)
+	assert.Equal(t, refreshExpiryTime, res.Data.Refresh.ExpiresAt)
+
+	assert.Equal(t, gock.IsDone(), true)
+}