public void MinimumValue()
{
var tree = new BinarySearchTree<int> {15, 6, 18, 3};
Assert.That(tree.Minimum(), Is.EqualTo(3));
}
public void MinimumCalledOnEmptyTreeCausesException()
{
var tree = new BinarySearchTree<int>();
Assert.Throws<InvalidOperationException>(() => tree.Minimum());
}
