==================
Simple Function Call
==================

(output 'hi')

---

(root
  (block
    (statement
      (expression
        (function_call
          (built_in_function
            (expression
              (value
                (string)))))))))

==================
Nested Function Call
==================

(assert_equal (random_integer) 4)
assert_equal random_integer 4

---

(root
  (block
    (statement
      (expression
        (function_call
          (built_in_function
            (expression
              (function_call
                (built_in_function)))
            (expression
              (value
                (integer)))))))
    (statement
      (expression
        (function_call
          (built_in_function
            (expression
              (function_call
                (built_in_function
                  (expression
                    (value
                      (integer))))))))))))