Fixed Stepper allows incrementing beyond the maximum value (#28398)

* Fix for stepper allows to increment value

* Updating naming concern

* Updates on minimum value and test case sample

Author: SubhikshaSf4851

src/Controls/src/Core/Stepper/Stepper.cs

@@ -12,7 +12,7 @@ public partial class Stepper : View, IElementConfiguration<Stepper>, IStepper
 	{
 		/// <summary>Bindable property for <see cref="Maximum"/>.</summary>
 		public static readonly BindableProperty MaximumProperty = BindableProperty.Create(nameof(Maximum), typeof(double), typeof(Stepper), 100.0,
-			validateValue: (bindable, value) => (double)value > ((Stepper)bindable).Minimum,
+			validateValue: (bindable, value) => (double)value >= ((Stepper)bindable).Minimum,
 			coerceValue: (bindable, value) =>
 			{
 				var stepper = (Stepper)bindable;
@@ -22,7 +22,7 @@ public partial class Stepper : View, IElementConfiguration<Stepper>, IStepper
 
 		/// <summary>Bindable property for <see cref="Minimum"/>.</summary>
 		public static readonly BindableProperty MinimumProperty = BindableProperty.Create(nameof(Minimum), typeof(double), typeof(Stepper), 0.0,
-			validateValue: (bindable, value) => (double)value < ((Stepper)bindable).Maximum,
+			validateValue: (bindable, value) => (double)value <= ((Stepper)bindable).Maximum,
 			coerceValue: (bindable, value) =>
 			{
 				var stepper = (Stepper)bindable;

src/Controls/tests/TestCases.HostApp/Issues/Issue28330.cs

@@ -0,0 +1,52 @@
+namespace Maui.Controls.Sample.Issues;
+[Issue(IssueTracker.Github, 28330, "Stepper allows to increment when value equals to maximum", PlatformAffected.All)]
+public class Issue28330 : TestContentPage
+{
+    protected override void Init()
+    {
+        var layout = new StackLayout { };
+
+        Stepper Incrementstepper = new Stepper
+        {
+            AutomationId = "Incrementstepper",
+            HorizontalOptions = LayoutOptions.Center,
+            Increment = 1,
+            Minimum = 1,
+            Maximum = 1,
+            Value = 1
+        };
+
+        Label Incrementlabel = new Label
+        {
+            AutomationId = "Incrementlabel",
+            HorizontalOptions = LayoutOptions.Center,
+            FontSize = 32
+        };
+        Incrementlabel.SetBinding(Label.TextProperty, new Binding("Value", source: Incrementstepper));
+
+        Stepper Decrementstepper = new Stepper
+        {
+            AutomationId = "Decrementstepper",
+            HorizontalOptions = LayoutOptions.Center,
+            Increment = 1,
+            Maximum = 1,
+            Minimum = 1,
+            Value = 1
+        };
+
+        Label Decrementlabel = new Label
+        {
+            AutomationId = "Decrementlabel",
+            HorizontalOptions = LayoutOptions.Center,
+            FontSize = 32
+        };
+        Decrementlabel.SetBinding(Label.TextProperty, new Binding("Value", source: Decrementstepper));
+
+        layout.Children.Add(Incrementstepper);
+        layout.Children.Add(Incrementlabel);
+        layout.Children.Add(Decrementstepper);
+        layout.Children.Add(Decrementlabel);
+
+        Content = layout;
+    }
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28330.cs

@@ -0,0 +1,24 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+public class Issue28330 : _IssuesUITest
+{
+    public Issue28330(TestDevice device) : base(device)
+    {
+    }
+
+    public override string Issue => "Stepper allows to increment when value equals to maximum";
+
+    [Test]
+    [Category(UITestCategories.Stepper)]
+    public void Issue28330StepperIncrementShouldBeDisabled()
+    {
+        App.WaitForElement("Incrementlabel");
+        App.IncreaseStepper("Incrementstepper");
+        Assert.That(App.FindElement("Incrementlabel").GetText(), Is.EqualTo("1"));
+        App.DecreaseStepper("Decrementstepper");
+        Assert.That(App.FindElement("Decrementlabel").GetText(), Is.EqualTo("1"));
+    }
+}