Merge pull request #60 from engunneer/bug/compareTo

Fix comparisons

Source/Meadow.Units.Tests/CommonTests.cs

@@ -0,0 +1,42 @@
+using Xunit;
+using System;
+using System.Linq;
+using Meadow.Units;
+
+namespace Meadow.Units.Tests;
+
+public class CommonTests
+{
+    [Fact]
+    public void CompareToObjectOfSameType()
+    {
+        // find all comparable structs in the assembly
+        var testTypes = typeof(Temperature)
+            .Assembly
+            .GetTypes()
+            .Where(t => t.IsValueType && typeof(IComparable).IsAssignableFrom(t))
+            .ToArray();
+
+        var failCount = 0;
+        var successCount = 0;
+
+        foreach (var t in testTypes)
+        {
+            var testItemA = Activator.CreateInstance(t);
+            var testItemB = Activator.CreateInstance(t);
+
+            try
+            {
+                var shouldBeZero = (testItemA as IComparable).CompareTo(testItemB);
+                Assert.Equal(0, shouldBeZero);
+                successCount++;
+            }
+            catch (Exception)
+            {
+                failCount++;
+            }
+        }
+
+        Assert.True(failCount == 0, $"{failCount} out of {failCount + successCount} failed CompareTo(object)");
+    }
+}