public void DoesNotPartitionArraysWithTwoItems()
{
// Arrange
var pivot = new Pivot(new[] { 0, 0 });
// Act
var result = pivot.Partition(0, 0, 0);
// Assert
Assert.AreEqual(-1, result);
}
public void SucceedsOnRandomArray()
{
// Arrange
var array = GetRandomArray();
var pivot = new Pivot(array);
// Act
var result = pivot.Partition(0, array.Length - 1, 450);
// Assert
AssertItemsLeftOfPivotAreLessThanIt(array, result);
AssertItemsRightOfPivotAreGreaterOrEqualOfIt(array, result);
}
public void ThreeItemsArray()
{
// Arrange
var array = new[] { 10, 5, 1 };
var pivot = new Pivot(array);
// Act
var result = pivot.Partition(0, array.Length - 1, 5);
// Assert
Assert.AreEqual(1, result);
Assert.AreEqual(1, array[0]);
Assert.AreEqual(5, array[1]);
Assert.AreEqual(10, array[2]);
}
public void PivotDoesNotNeedToExistOnArrayForPartitionToWork()
{
// Arrange
var array = new[] { 10, 5, 1, 8 };
var pivot = new Pivot(array);
// Act
var result = pivot.Partition(0, array.Length - 1, 2);
// Assert
Assert.AreEqual(1, result);
Assert.AreEqual(1, array[0]);
Assert.AreEqual(5, array[1]);
Assert.IsTrue(array[2] > 5);
Assert.IsTrue(array[3] > 5);
}
public void FiveItemsArray()
{
// Arrange
var array = new[] { 10, 5, 1, 8, -63 };
var pivot = new Pivot(array);
// Act
var result = pivot.Partition(0, array.Length - 1, 5);
// Assert
Assert.AreEqual(2, result);
Assert.IsTrue(array[0] < 5);
Assert.IsTrue(array[1] < 5);
Assert.AreEqual(5, array[2]);
Assert.IsTrue(array[3] > 5);
Assert.IsTrue(array[4] > 5);
}