public void PermMissingElemSolutionTest()
{
var missingElement = new PermMissingElem();
//N = 4
int[] array = new int[] { 2, 3, 1, 5 };
int result = missingElement.Solve(array);
Assert.AreEqual(4, result);
//N = 1
array = new int[] { 2 };
result = missingElement.Solve(array);
Assert.AreEqual(1, result);
}