| Aspect Tested | Test | Expected Outcome | Actual Outcome |
|---|---|---|---|
| + operator | 1 3 + | (1+3) | (1+3) |
| - operator | 1 3 - | (1-3) | (1-3) |
| * operator | 1 3 * | (1*3) | (1*3) |
| / operator | 1 3 / | (1/3) | (1/3) |
| Infix expression with parentheses | 1 2 + 3 4 + * | ((1+2)*(3+4)) | ((1+2)*(3+4)) |
| Expression without spaces | 1 4 3*+ 2+ | ((1+(4*3))+2) | ((1+(4*3))+2) |
| Invalid operator | 1 2 + 3 + 4 & | Invalid token & | Invalid token & |
| Invalid token beginning with a digit | 1a 3 + | Invalid token a | Invalid token a |