bugfix: added tests for legend menu builder class

GsaGHTests/Helpers/GH/Legend/LegendMenuBuilderTests.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Windows.Forms;
+
+using GsaGH.Components;
+using GsaGH.Helpers;
+
+using Moq;
+
+using Xunit;
+
+namespace GsaGH.Tests.Helpers {
+  [Collection("GrasshopperFixture collection")]
+  public class LegendMenuBuilderTests {
+    private Mock<Contour1dResults> _componentMock;
+    private double _initialScale;
+    private ToolStripMenuItem _menuItem;
+
+    public LegendMenuBuilderTests() {
+      _componentMock = new Mock<Contour1dResults>(); // any component you want
+      var updateUiMock = new Mock<Action>();
+      var setLegendScaleMock = new Mock<LegendMenuBuilder.SetLegendScaleDelegate>();
+      _initialScale = 1.5;
+      var builder = new LegendMenuBuilder();
+
+      _menuItem = builder.CreateLegendToolStripMenuItem(_componentMock.Object, updateUiMock.Object,
+        setLegendScaleMock.Object, _initialScale);
+    }
+
+    [Fact]
+    public void CreateLegendToolStripMenuItem_CreatesMenuItemCorrectly() {
+      Assert.NotNull(_menuItem);
+      Assert.Equal("Scale Legend", _menuItem.Text);
+      Assert.True(_menuItem.Enabled);
+      Assert.NotNull(_menuItem.DropDownItems);
+      Assert.Equal(_initialScale.ToString(), _menuItem.DropDownItems[0]?.Text);
+    }
+
+    [Fact]
+    public void CreateLegendToolStripMenuItem_UpdatesScale_OnTextChange() {
+      ToolStripItem scaleTextBox = _menuItem.DropDownItems[0];
+      double newScale = 2.5d;
+      // Act - Simulate text change
+      scaleTextBox.Text = $"{newScale}"; // Updates private _scaleLegendTxt indirectly
+      _menuItem.DropDownItems[1].PerformClick(); // Simulate mouse up to trigger UpdateLegendScale
+
+      Assert.Equal(newScale.ToString(), _menuItem.DropDownItems[0]?.Text);
+    }
+  }
+}