Fixed tests

PixiEditorTests/ApplicationFixture.cs

@@ -1,6 +1,8 @@
 using System.Diagnostics.CodeAnalysis;
+using System.IO;
 using System.Windows;
 using PixiEditor;
+using PixiEditor.Models.Undo;
 
 namespace PixiEditorTests
 {
@@ -14,6 +16,11 @@ namespace PixiEditorTests
                 App app = new App();
                 app.InitializeComponent();
             }
+
+            if (!Directory.Exists(Path.GetDirectoryName(StorageBasedChange.DefaultUndoChangeLocation)))
+            {
+                Directory.CreateDirectory(StorageBasedChange.DefaultUndoChangeLocation);
+            }
         }
     }
 }

PixiEditorTests/ModelsTests/DataHoldersTests/DocumentTests.cs

@@ -1,13 +1,16 @@
 using System;
+using System.IO;
 using System.Windows.Media;
 using PixiEditor.Models.Controllers;
 using PixiEditor.Models.DataHolders;
 using PixiEditor.Models.Enums;
 using PixiEditor.Models.Position;
+using PixiEditor.Models.Undo;
 using Xunit;
 
 namespace PixiEditorTests.ModelsTests.DataHoldersTests
 {
+    [Collection("Application collection")]
     public class DocumentTests
     {
         [Theory]