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Added more unit tests to the floating point helper classes; Variegator unit test is now internal

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git-svn-id: file:///srv/devel/repo-conversion/nusu@287 d2e56fa2-650e-0410-a79f-9358c0239efd
This commit is contained in:
Markus Ewald 2013-07-15 13:38:21 +00:00
parent 2462dd6dc4
commit 63ddef021d
7 changed files with 92 additions and 10 deletions
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55
Source/FloatHelper.Test.cs
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@ -29,11 +29,11 @@ namespace Nuclex.Support {
/// <summary>Unit Test for the FloatHelper class</summary>
[TestFixture]
internal class FloatHelperTest {
public class FloatHelperTest {
/// <summary>Tests the floating point value comparison helper</summary>
[Test]
public void TestFloatComparison() {
public void UlpDistancesOnFloatsCompareAsEqual() {
Assert.IsTrue(
FloatHelper.AreAlmostEqual(0.00000001f, 0.0000000100000008f, 1),
"Minimal difference between very small floating point numbers is considered equal"
@ -55,7 +55,7 @@ namespace Nuclex.Support {
/// <summary>Tests the double precision floating point value comparison helper</summary>
[Test]
public void TestDoubleComparison() {
public void UlpDistancesOnDoublesCompareAsEqual() {
Assert.IsTrue(
FloatHelper.AreAlmostEqual(0.00000001, 0.000000010000000000000002, 1),
"Minimal difference between very small double precision floating point " +
@ -81,7 +81,7 @@ namespace Nuclex.Support {
/// <summary>Tests the integer reinterpretation functions</summary>
[Test]
public void TestIntegerReinterpretation() {
public void IntegersCanBeReinterpretedAsFloats() {
Assert.AreEqual(
12345.0f,
FloatHelper.ReinterpretAsFloat(FloatHelper.ReinterpretAsInt(12345.0f)),
@ -91,7 +91,7 @@ namespace Nuclex.Support {
/// <summary>Tests the long reinterpretation functions</summary>
[Test]
public void TestLongReinterpretation() {
public void LongsCanBeReinterpretedAsDoubles() {
Assert.AreEqual(
12345.67890,
FloatHelper.ReinterpretAsDouble(FloatHelper.ReinterpretAsLong(12345.67890)),
@ -101,7 +101,7 @@ namespace Nuclex.Support {
/// <summary>Tests the floating point reinterpretation functions</summary>
[Test]
public void TestFloatReinterpretation() {
public void FloatsCanBeReinterpretedAsIntegers() {
Assert.AreEqual(
12345,
FloatHelper.ReinterpretAsInt(FloatHelper.ReinterpretAsFloat(12345)),
@ -109,12 +109,33 @@ namespace Nuclex.Support {
);
}
/// <summary>
/// Verifies that the IsZero() method can distinguish zero from very small values
/// </summary>
[Test]
public void CanDetermineIfFloatIsZero() {
Assert.IsTrue(FloatHelper.IsZero(FloatHelper.PositiveZeroFloat));
Assert.IsTrue(FloatHelper.IsZero(FloatHelper.NegativeZeroFloat));
Assert.IsFalse(FloatHelper.IsZero(1.401298E-45f));
Assert.IsFalse(FloatHelper.IsZero(-1.401298E-45f));
}
/// <summary>
/// Verifies that the IsZero() method can distinguish zero from very small values
/// </summary>
[Test]
public void CanDetermineIfDoubleIsZero() {
Assert.IsTrue(FloatHelper.IsZero(FloatHelper.PositiveZeroDouble));
Assert.IsTrue(FloatHelper.IsZero(FloatHelper.NegativeZeroDouble));
Assert.IsFalse(FloatHelper.IsZero(4.94065645841247E-324));
Assert.IsFalse(FloatHelper.IsZero(-4.94065645841247E-324));
}
/// <summary>
/// Tests the double prevision floating point reinterpretation functions
/// </summary>
[Test]
public void TestDoubleReinterpretation() {
public void DoublesCanBeReinterpretedAsLongs() {
Assert.AreEqual(
1234567890,
FloatHelper.ReinterpretAsLong(FloatHelper.ReinterpretAsDouble(1234567890)),
@ -122,6 +143,26 @@ namespace Nuclex.Support {
);
}
// http://www.altdevblogaday.com/2012/02/22/comparing-floating-point-numbers-2012-edition/
// Make both positive
// If both are negative -> fine
// If both are positive -> fine
// If different -> Measure both distances to zero in ulps and sum them
public void NegativeZeroEqualsPositiveZero() {
float zero = 0.0f;
float zeroPlusOneUlp = FloatHelper.ReinterpretAsFloat(
FloatHelper.ReinterpretAsInt(zero) + 1
);
float zeroMinusOneUlp = -zeroPlusOneUlp;
bool test = FloatHelper.AreAlmostEqual(zeroMinusOneUlp, zeroPlusOneUlp, 1);
Assert.IsFalse(FloatHelper.AreAlmostEqual(zero, zeroPlusOneUlp, 0));
Assert.IsTrue(FloatHelper.AreAlmostEqual(zero, zeroPlusOneUlp, 1));
Assert.IsFalse(FloatHelper.AreAlmostEqual(zero, zeroMinusOneUlp, 0));
Assert.IsTrue(FloatHelper.AreAlmostEqual(zero, zeroMinusOneUlp, 1));
}
}
} // namespace Nuclex.Support