public void Addition_and_subtraction()
 {
     Assert.Equal(8, Wordy.Answer("What is 1 plus 5 minus -2?"));
 }
 public void Multiple_subtraction()
 {
     Assert.Equal(3, Wordy.Answer("What is 20 minus 4 minus 13?"));
 }
 public void Division()
 {
     Assert.Equal(-11, Wordy.Answer("What is 33 divided by -3?"));
 }
 public void Multiple_additions()
 {
     Assert.Equal(3, Wordy.Answer("What is 1 plus 1 plus 1?"));
 }
 public void Multiple_division()
 {
     Assert.Equal(2, Wordy.Answer("What is -12 divided by 2 divided by -3?"));
 }
 public void Reject_problem_missing_an_operand()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("What is 1 plus?"));
 }
 public void Addition_with_negative_numbers()
 {
     Assert.Equal(-11, Wordy.Answer("What is -1 plus -10?"));
 }
 public void Multiple_multiplication()
 {
     Assert.Equal(-12, Wordy.Answer("What is 2 multiplied by -2 multiplied by 3?"));
 }
 public void Reject_prefix_notation()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("What is plus 1 2?"));
 }
 public void More_addition()
 {
     Assert.Equal(55, Wordy.Answer("What is 53 plus 2?"));
 }
 public void Addition()
 {
     Assert.Equal(2, Wordy.Answer("What is 1 plus 1?"));
 }
 public void Reject_two_numbers_in_a_row()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("What is 1 plus 2 1?"));
 }
 public void Reject_problem_with_no_operands_or_operators()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("What is?"));
 }
 public void Subtraction_then_addition()
 {
     Assert.Equal(14, Wordy.Answer("What is 17 minus 6 plus 3?"));
 }
 public void Large_addition()
 {
     Assert.Equal(45801, Wordy.Answer("What is 123 plus 45678?"));
 }
 public void Just_a_number()
 {
     Assert.Equal(5, Wordy.Answer("What is 5?"));
 }
 public void Subtraction()
 {
     Assert.Equal(16, Wordy.Answer("What is 4 minus -12?"));
 }
 public void Addition_and_multiplication()
 {
     Assert.Equal(-8, Wordy.Answer("What is -3 plus 7 multiplied by -2?"));
 }
 public void Multiplication()
 {
     Assert.Equal(-75, Wordy.Answer("What is -3 multiplied by 25?"));
 }
 public void Unknown_operation()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("What is 52 cubed?"));
 }
 public void Non_math_question()
 {
     Assert.Throws <ArgumentException>(() => Wordy.Answer("Who is the President of the United States?"));
 }