Move test assertions into a test function

tests/native_tests/native_macros.hy

@@ -15,8 +15,7 @@
   (rev (.append x 1) (.append x 2) (.append x 3))
   (assert (= x [3 2 1])))
 
-; Macros returning constants
-
+(defn test-macros-returning-constants []
   (defmacro an-int [] 42)
   (assert (= (an-int) 42))
 
@@ -50,7 +49,8 @@
   (assert (= (a-set) #{1 2}))
 
   (defmacro a-none [])
-(assert (= (a-none) None))
+  (assert (= (a-none) None)))
+
 
 ; A macro calling a previously defined function
 (eval-when-compile