add validator + tests

config/smtp.go

@@ -1,39 +1,31 @@
 package config
 
 import (
-	"errors"
 	"fmt"
+
+	"github.com/go-playground/validator/v10"
 )
 
 // SMTPConfig handles mandatory parameters for the STMP server connection
 type SMTPConfig struct {
-	User     string
-	Password string
-	Url      string
-	Port     string
+	User     string `validate:"required"`
+	Password string `validate:"required"`
+	Url      string `validate:"required"`
+	Port     string `validate:"required"`
 }
 
 func NewSMTPConfig(user, password, url, port string) (SMTPConfig, error) {
-	var config SMTPConfig
-	if user == "" {
-		return config, errors.New("SMTP user can't be empty")
+	config := SMTPConfig{
+		User:     user,
+		Password: password,
+		Url:      url,
+		Port:     port,
 	}
-	config.User = user
 
-	if password == "" {
-		return config, errors.New("SMTP password can't be empty")
+	validate := validator.New(validator.WithRequiredStructEnabled())
+	if err := validate.Struct(config); err != nil {
+		return config, err
 	}
-	config.Password = password
-
-	if url == "" {
-		return config, errors.New("SMTP server url can't be empty")
-	}
-	config.Url = url
-
-	if port == "" {
-		return config, errors.New("SMTP server port can't be empty")
-	}
-	config.Port = port
 
 	return config, nil
 }

config/smtp_test.go

@@ -0,0 +1,26 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/go-playground/validator/v10"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSMTPConfig(t *testing.T) {
+	t.Run("right config", func(t *testing.T) {
+		_, err := NewSMTPConfig("test", "test", "test", "test")
+		require.NoError(t, err)
+	})
+
+	t.Run("empty user", func(t *testing.T) {
+		_, err := NewSMTPConfig("", "test", "test", "test")
+		require.Error(t, err)
+
+		_, ok := err.(*validator.InvalidValidationError)
+		require.False(t, ok)
+
+		assert.Contains(t, err.Error(), "validation for 'User'")
+	})
+}