public void TestInvalidAnswer()
{
PuzzleEquation puzzleEquation = new PuzzleEquation();
string s = puzzleEquation.checkAnswer("abc");
Assert.AreEqual(s, "Invalid number(must be a number)");
}
public void TestCorrectAnswer()
{
PuzzleEquation puzzleEquation = new PuzzleEquation();
puzzleEquation.setPuzzle(3, 3);
string s = puzzleEquation.checkAnswer("6");
Assert.AreEqual(s, "correct");
}