bugfix: unit tests for conour legend

GsaGHTests/Helpers/GH/Legend/ContourLegendTests.cs

@@ -1,22 +1,45 @@
-using GsaGH.Helpers;
+using System.Drawing;
+
+using GsaGH.Helpers;
 using GsaGH.Helpers.GH;
 
 using Moq;
 
 using Xunit;
 
 namespace GsaGHTests.Helpers {
+  [Collection("GrasshopperFixture collection")]
   public class ContourLegendTests {
+    private readonly Mock<IContourLegendConfiguration> _mockConfiguration;
+    private readonly ContourLegend legend;
+    private readonly Bitmap _mockBitmap;
+
+    public ContourLegendTests() {
+      _mockBitmap = new Bitmap(10, 10);
+      _mockConfiguration = new Mock<IContourLegendConfiguration>();
+      _mockConfiguration.Setup(c => c.Bitmap).Returns(_mockBitmap);
+      _mockConfiguration.Setup(c => c.Scale).Returns(1.0);
+      legend = new ContourLegend(_mockConfiguration.Object);
+    }
+
     [Fact]
     public void Constructor_InitializesConfiguration() {
-      // Arrange
-      var mockConfiguration = new Mock<IContourLegendConfiguration>();
+      Assert.NotNull(legend);
+    }
 
-      // Act
-      var legend = new ContourLegend(mockConfiguration.Object);
+    [Fact]
+    public void DrawGradientLegend_UpdatesBitmapCorrectly() {
+      var color = Color.FromArgb(0, 255, 255, 0);
+      legend.DrawGradientLegend(2, 5, color);
 
-      // Assert
-      Assert.NotNull(legend);
+      for (int y = 2; y < 5; y++) {
+        for (int x = 0; x < _mockBitmap.Width; x++) {
+          Assert.Equal(color, _mockBitmap.GetPixel(x, _mockBitmap.Height - y - 1));
+        }
+      }
     }
+    //other methods need to be tested manually or by integration tests. 
+    //we are not able to mock or inherit DisplayPipeline(which is needed to draw stuff)
+    //so we aren't able to check if drawings are correct
   }
 }