test: add pagination tests.

src/Ursa/Controls/Pagination/Pagination.cs

@@ -197,6 +197,7 @@ public class Pagination : TemplatedControl
 
     private void OnPageSizeChanged(AvaloniaPropertyChangedEventArgs<int> args)
     {
+        if (!IsInitialized) return;
         var pageCount = TotalCount / args.NewValue.Value;
         var residue = TotalCount % args.NewValue.Value;
         if (residue > 0) pageCount++;
@@ -305,16 +306,15 @@ public class Pagination : TemplatedControl
     {
         if (PageSize == 0) return;
         var pageCount = TotalCount / PageSize;
+        var currentPage = CurrentPage;
+        var residue = TotalCount % PageSize;
+        if (residue > 0) pageCount++;
         if (_buttonPanel is null)
         {
             SetCurrentValue(PageCountProperty, pageCount);
             return;
         }
         
-        var currentPage = CurrentPage;
-        var residue = TotalCount % PageSize;
-        if (residue > 0) pageCount++;
-
         if (pageCount <= 7)
         {
             for (var i = 0; i < 7; i++)

tests/HeadlessTest.Ursa/Controls/PaginationTests/PaginationTests.cs

@@ -0,0 +1,279 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml.MarkupExtensions;
+using Avalonia.Threading;
+using HeadlessTest.Ursa.TestHelpers;
+using Ursa.Controls;
+
+namespace HeadlessTest.Ursa.Controls.PaginationTests;
+
+public class PaginationTests
+{
+    [AvaloniaFact]
+    public void CurrentPage_Can_Be_Initialized()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void CurrentPage_Can_Be_Initialized_With_Another_Initialization_Order()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            TotalCount = 300,
+            PageSize = 50,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void Change_TotalCount_Should_Update_PageCount()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        pagination.TotalCount = 500;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(10, pagination.PageCount);
+        Assert.Equal(500, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void Change_PageSize_Should_Update_PageCount()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        pagination.PageSize = 100;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(3, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(100, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+    }
+
+    [AvaloniaFact]
+    public void Change_TotalCount_Clamps_Current_Page()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        pagination.TotalCount = 10;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(1, pagination.PageCount);
+        Assert.Equal(10, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(1, pagination.CurrentPage);
+    }
+
+    [AvaloniaFact]
+    public void CurrentPage_Is_Clamped()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        pagination.CurrentPage = 10;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(6, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void CurrentPage_Is_Clamped_When_PageCount_Changes()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        pagination.TotalCount = 10;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(1, pagination.PageCount);
+        Assert.Equal(10, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(1, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void Click_Next_Button_Should_Increment_CurrentPage()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        var nextButton = pagination.GetTemplateChildOfType<Button>(Pagination.PART_NextButton);
+        nextButton?.RaiseEvent(new RoutedEventArgs(Button.ClickEvent));
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(4, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void Click_Previous_Button_Should_Decrement_CurrentPage()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 3,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(3, pagination.CurrentPage);
+        var previousButton = pagination.GetTemplateChildOfType<Button>(Pagination.PART_PreviousButton);
+        previousButton?.RaiseEvent(new RoutedEventArgs(Button.ClickEvent));
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(2, pagination.CurrentPage);
+    }
+    
+    [AvaloniaFact]
+    public void Previous_Or_Next_Button_Is_Disabled_When_CurrentPage_Is_Min_Or_Max()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 1,
+            PageSize = 50,
+            TotalCount = 300,
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(1, pagination.CurrentPage);
+        var previousButton = pagination.GetTemplateChildOfType<Button>(Pagination.PART_PreviousButton);
+        var nextButton = pagination.GetTemplateChildOfType<Button>(Pagination.PART_NextButton);
+        Assert.False(previousButton?.IsEnabled);
+        Assert.True(nextButton?.IsEnabled);
+        pagination.CurrentPage = 6;
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(6, pagination.PageCount);
+        Assert.Equal(300, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(6, pagination.CurrentPage);
+        Assert.True(previousButton?.IsEnabled);
+        Assert.False(nextButton?.IsEnabled);
+    }
+    
+    [AvaloniaFact]
+    public void TinyPagination_Should_Calculate_PageCount_Correctly()
+    {
+        var window = new Window();
+        var pagination = new Pagination
+        {
+            CurrentPage = 1,
+            PageSize = 50,
+            TotalCount = 10,
+            [!StyledElement.ThemeProperty] = new DynamicResourceExtension("TinyPagination")
+        };
+        window.Content = pagination;
+        window.Show();
+        Dispatcher.UIThread.RunJobs();
+        Assert.Equal(1, pagination.PageCount);
+        Assert.Equal(10, pagination.TotalCount);
+        Assert.Equal(50, pagination.PageSize);
+        Assert.Equal(1, pagination.CurrentPage);
+    }
+}