public void InvalidInputTest()
{
var tree = new TreeNode <int>(0, null);
TestHelpers.AssertExceptionThrown(() => { Question4_1.AreConnected(null, tree); }, typeof(ArgumentNullException));
TestHelpers.AssertExceptionThrown(() => { Question4_1.AreConnected(tree, null); }, typeof(ArgumentNullException));
}
private static void ValidateResult <T>(TreeNode <T> first, TreeNode <T> second, bool expectedValue)
where T : IEquatable <T>
{
Assert.AreEqual(expectedValue, Question4_1.AreConnected(first, second));
}