| ConstantTest | Checks if a variable is the exact same value as a constant. |
| DefinedTest | Checks if a variable is defined in the current context. |
| DivisiblebyTest | Checks if a variable is divisible by a number. |
| EvenTest | Checks if a number is even. |
| NullTest | Checks that a variable is null. |
| OddTest | Checks if a number is odd. |
| SameasTest | Checks if a variable is the same as another one (=== in PHP). |
