Update gallery UpdatedAt timestamp on contents change (#3771)

* Update gallery updatedAt on content change
* Update gallery in UI on image change

pkg/models/update_test.go

@@ -0,0 +1,92 @@
+package models
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestUpdateIDs_ImpactedIDs(t *testing.T) {
+	tests := []struct {
+		name     string
+		IDs      []int
+		Mode     RelationshipUpdateMode
+		existing []int
+		want     []int
+	}{
+		{
+			name:     "add",
+			IDs:      []int{1, 2, 3},
+			Mode:     RelationshipUpdateModeAdd,
+			existing: []int{1, 2},
+			want:     []int{3},
+		},
+		{
+			name:     "remove",
+			IDs:      []int{1, 2, 3},
+			Mode:     RelationshipUpdateModeRemove,
+			existing: []int{1, 2},
+			want:     []int{1, 2},
+		},
+		{
+			name:     "set",
+			IDs:      []int{1, 2, 3},
+			Mode:     RelationshipUpdateModeSet,
+			existing: []int{1, 2},
+			want:     []int{3},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			u := &UpdateIDs{
+				IDs:  tt.IDs,
+				Mode: tt.Mode,
+			}
+			if got := u.ImpactedIDs(tt.existing); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("UpdateIDs.ImpactedIDs() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestUpdateIDs_EffectiveIDs(t *testing.T) {
+	tests := []struct {
+		name     string
+		IDs      []int
+		Mode     RelationshipUpdateMode
+		existing []int
+		want     []int
+	}{
+		{
+			name:     "add",
+			IDs:      []int{2, 3},
+			Mode:     RelationshipUpdateModeAdd,
+			existing: []int{1, 2},
+			want:     []int{1, 2, 3},
+		},
+		{
+			name:     "remove",
+			IDs:      []int{2, 3},
+			Mode:     RelationshipUpdateModeRemove,
+			existing: []int{1, 2},
+			want:     []int{1},
+		},
+		{
+			name:     "set",
+			IDs:      []int{1, 2, 3},
+			Mode:     RelationshipUpdateModeSet,
+			existing: []int{1, 2},
+			want:     []int{1, 2, 3},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			u := &UpdateIDs{
+				IDs:  tt.IDs,
+				Mode: tt.Mode,
+			}
+			if got := u.EffectiveIDs(tt.existing); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("UpdateIDs.EffectiveIDs() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}