[TESTS] auth LinkAccount test coverage (squash)

(cherry picked from commit a2b2e3066b)

models/auth/source.go

@@ -5,6 +5,7 @@
 package auth
 
 import (
+	"context"
 	"fmt"
 	"reflect"
 
@@ -306,6 +307,17 @@ func GetSourceByID(id int64) (*Source, error) {
 	return source, nil
 }
 
+func GetSourceByName(ctx context.Context, name string) (*Source, error) {
+	source := &Source{}
+	has, err := db.GetEngine(ctx).Where("name = ?", name).Get(source)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrSourceNotExist{}
+	}
+	return source, nil
+}
+
 // UpdateSource updates a Source record in DB.
 func UpdateSource(source *Source) error {
 	var originalSource *Source