using System;
using System.Collections.Generic;

using NUnit.Framework;

namespace Nuclex.Support {

  /// <summary>Contains unit tests for the integer helper class</summary>
  [TestFixture]
  public class IntegerHelperTest {

    /// <summary>
    ///   Verifies that the next power of 2 calculation works for long integers
    /// </summary>
    [Test]
    public void TestNextPowerOf2ULong() {
      Assert.AreEqual(1UL, IntegerHelper.NextPowerOf2(0UL));
      Assert.AreEqual(1UL, IntegerHelper.NextPowerOf2(1UL));
      Assert.AreEqual(2UL, IntegerHelper.NextPowerOf2(2UL));
      Assert.AreEqual(4UL, IntegerHelper.NextPowerOf2(3UL));
      Assert.AreEqual(4UL, IntegerHelper.NextPowerOf2(4UL));
      Assert.AreEqual(
        9223372036854775808UL, IntegerHelper.NextPowerOf2(9223372036854775807UL)
      );
      Assert.AreEqual(
        9223372036854775808UL, IntegerHelper.NextPowerOf2(9223372036854775808UL)
      );
    }

    /// <summary>
    ///   Verifies that the next power of 2 calculation works for long integers
    /// </summary>
    [Test]
    public void TestNextPowerOf2Long() {
      Assert.AreEqual(1L, IntegerHelper.NextPowerOf2(0L));
      Assert.AreEqual(1L, IntegerHelper.NextPowerOf2(1L));
      Assert.AreEqual(2L, IntegerHelper.NextPowerOf2(2L));
      Assert.AreEqual(4L, IntegerHelper.NextPowerOf2(3L));
      Assert.AreEqual(4L, IntegerHelper.NextPowerOf2(4L));
      Assert.AreEqual(4611686018427387904L, IntegerHelper.NextPowerOf2(4611686018427387903L));
      Assert.AreEqual(4611686018427387904L, IntegerHelper.NextPowerOf2(4611686018427387904L));
    }

    /// <summary>
    ///   Verifies that the next power of 2 calculation works for integers
    /// </summary>
    [Test]
    public void TestNextPowerOf2UInt() {
      Assert.AreEqual(1U, IntegerHelper.NextPowerOf2(0U));
      Assert.AreEqual(1U, IntegerHelper.NextPowerOf2(1U));
      Assert.AreEqual(2U, IntegerHelper.NextPowerOf2(2U));
      Assert.AreEqual(4U, IntegerHelper.NextPowerOf2(3U));
      Assert.AreEqual(4U, IntegerHelper.NextPowerOf2(4U));
      Assert.AreEqual(2147483648U, IntegerHelper.NextPowerOf2(2147483647U));
      Assert.AreEqual(2147483648U, IntegerHelper.NextPowerOf2(2147483648U));
    }

    /// <summary>
    ///   Verifies that the next power of 2 calculation works for integers
    /// </summary>
    [Test]
    public void TestNextPowerOf2Int() {
      Assert.AreEqual(1, IntegerHelper.NextPowerOf2(0));
      Assert.AreEqual(1, IntegerHelper.NextPowerOf2(1));
      Assert.AreEqual(2, IntegerHelper.NextPowerOf2(2));
      Assert.AreEqual(4, IntegerHelper.NextPowerOf2(3));
      Assert.AreEqual(4, IntegerHelper.NextPowerOf2(4));
      Assert.AreEqual(1073741824, IntegerHelper.NextPowerOf2(1073741823));
      Assert.AreEqual(1073741824, IntegerHelper.NextPowerOf2(1073741824));
    }


  }

} // namespace Nuclex.Support