Added helper class for floating point operations; implemented advanced floating point comparison

git-svn-id: file:///srv/devel/repo-conversion/nusu@72 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/FloatHelper.Test.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+
+#if UNITTEST
+
+using NUnit.Framework;
+
+namespace Nuclex.Support {
+
+  /// <summary>Unit Test for the FloatHelper class</summary>
+  [TestFixture]
+  public class FloatHelperTest {
+
+    /// <summary>Tests the floating point value comparison helper</summary>
+    [Test]
+    public void TestFloatComparison() {
+      Assert.IsTrue(
+        FloatHelper.AreAlmostEqual(0.00000001f, 0.0000000100000008f, 1),
+        "Minimal difference between very small floating point numbers is considered equal"
+      );
+      Assert.IsFalse(
+        FloatHelper.AreAlmostEqual(0.00000001f, 0.0000000100000017f, 1),
+        "Larger difference between very small floating point numbers is not considered equal"
+      );
+
+      Assert.IsTrue(
+        FloatHelper.AreAlmostEqual(1000000.00f, 1000000.06f, 1),
+        "Minimal difference between very large floating point numbers is considered equal"
+      );
+      Assert.IsFalse(
+        FloatHelper.AreAlmostEqual(1000000.00f, 1000000.13f, 1),
+        "Larger difference between very large floating point numbers is not considered equal"
+      );
+    }
+
+    /// <summary>Tests the double precision floating point value comparison helper</summary>
+    [Test]
+    public void TestDoubleComparison() {
+      Assert.IsTrue(
+        FloatHelper.AreAlmostEqual(0.00000001, 0.000000010000000000000002, 1),
+        "Minimal difference between very small double precision floating point " +
+        "numbers is considered equal"
+      );
+      Assert.IsFalse(
+        FloatHelper.AreAlmostEqual(0.00000001, 0.000000010000000000000004, 1),
+        "Larger difference between very small double precision floating point " +
+        "numbers is not considered equal"
+      );
+
+      Assert.IsTrue(
+        FloatHelper.AreAlmostEqual(1000000.00, 1000000.0000000001, 1),
+        "Minimal difference between very large double precision floating point " +
+        "numbers is considered equal"
+      );
+      Assert.IsFalse(
+        FloatHelper.AreAlmostEqual(1000000.00, 1000000.0000000002, 1),
+        "Larger difference between very large double precision floating point " +
+        "numbers is not considered equal"
+      );
+    }
+
+  }
+
+} // namespace Nuclex.Support
+
+#endif // UNITTEST