feat: user repository interface get by username

error.go

@@ -6,6 +6,7 @@ var (
 	ErrContextNil              = errors.New("Context is nil")
 	ErrInvalidUsernamePassword = errors.New("Username and password invalid")
 	ErrUserNotAuthorized       = errors.New("User not authorized")
+	ErrUsernameHasBeenTaken    = errors.New("Username has been taken")
 )
 
 type customError struct {

inventar.go

@@ -14,4 +14,5 @@ type UserService interface {
 type UserRepository interface {
 	Signup(ctx context.Context, credential *Credential) (bool, error)
 	Signin(ctx context.Context, credential *Credential) (bool, error)
+	GetByUsername(ctx context.Context, username string) (*Credential, error)
 }

user/service.go

@@ -25,6 +25,16 @@ func (s *service) Signup(ctx context.Context, credential *inventar.Credential) (
 		return false, err
 	}
 
+	checkUsername, err := s.repository.GetByUsername(ctx, credential.Username)
+
+	if err != nil {
+		return false, err
+	}
+
+	if checkUsername.Username != "" {
+		return false, inventar.ErrUsernameHasBeenTaken
+	}
+
 	res, err := s.repository.Signup(ctx, credential)
 
 	if err != nil {

user/service_test.go

@@ -24,7 +24,10 @@ func TestSignup(t *testing.T) {
 		Password: "admin123",
 	}
 
+	mockCredentialEmpty := &inventar.Credential{}
+
 	r := new(mocks.UserRepository)
+	r.On("GetByUsername", mock.Anything, mockCredential.Username).Return(mockCredentialEmpty, nil)
 	r.On("Signup", mock.Anything, mockCredential).Return(true, nil)
 
 	v := inventar.NewValidator()
@@ -74,14 +77,57 @@ func TestSignupWithErrorValidate(t *testing.T) {
 	assert.False(t, res)
 }
 
+func TestSignupWithErrorGetByUsername(t *testing.T) {
+
+	mockCredential := &inventar.Credential{
+		Username: "admin",
+		Password: "admin123",
+	}
+
+	r := new(mocks.UserRepository)
+	r.On("GetByUsername", mock.Anything, mockCredential.Username).Return(nil, errors.New("Error"))
+
+	v := inventar.NewValidator()
+
+	s := NewService(r, v, timeout)
+
+	res, err := s.Signup(context.TODO(), mockCredential)
+
+	assert.Error(t, err)
+	assert.False(t, res)
+}
+
+func TestSignupWithUsernameHasBeenTaken(t *testing.T) {
+
+	mockCredential := &inventar.Credential{
+		Username: "admin",
+		Password: "admin123",
+	}
+
+	r := new(mocks.UserRepository)
+	r.On("GetByUsername", mock.Anything, mockCredential.Username).Return(mockCredential, nil)
+
+	v := inventar.NewValidator()
+
+	s := NewService(r, v, timeout)
+
+	res, err := s.Signup(context.TODO(), mockCredential)
+
+	assert.Error(t, err)
+	assert.False(t, res)
+}
+
 func TestSignupWithError(t *testing.T) {
 
 	mockCredential := &inventar.Credential{
 		Username: "admin",
 		Password: "admin123",
 	}
 
+	mockCredentialEmpty := &inventar.Credential{}
+
 	r := new(mocks.UserRepository)
+	r.On("GetByUsername", mock.Anything, mockCredential.Username).Return(mockCredentialEmpty, nil)
 	r.On("Signup", mock.Anything, mockCredential).Return(false, errors.New("Error"))
 
 	v := inventar.NewValidator()