public void InvalidInput()
{
Assert.Throws <ArgumentNullException>(() => InversePairsCount.GetCount(null));
Assert.Equal(0, InversePairsCount.GetCount(new int[0]));
}
public void TestWithRandomArray()
{
int[] array = GenerateArray(5000);
Assert.Equal(GetResultByBruteForce(array), InversePairsCount.GetCount(array));
}
public void TestWithSortedArray()
{
int[] array = GenerateArray(5000);
Array.Sort(array);
Assert.Equal(0, InversePairsCount.GetCount(array));
}
public void TestWithReverselySortedArray()
{
int[] array = GenerateArray(5000);
Array.Sort(array, (int a, int b) => b - a);
Assert.Equal(GetResultByBruteForce(array), InversePairsCount.GetCount(array));
}
public void ExampleOnBook()
{
Assert.Equal(5, InversePairsCount.GetCount(new[] { 7, 5, 6, 4 }));
}