Lisp unit tests for macros conventions and best practices

I find it hard to reason about macro-expansion and was wondering what the best practices were for testing them.

So if I have a macro, I can perform one level of macro expansion via macroexpand-1.

(defmacro incf-twice (n)
  `(progn
     (incf ,n)
     (incf ,n)))

for example

(macroexpand-1 '(incf-twice n))

evaluates to

(PROGN (INCF N) (INCF N))

It seems simple enough to turn this into a test for the macro.

(equalp (macroexpand-1 '(incf-twice n))
  '(progn (incf n) (incf n)))

Is there an established convention for organizing tests for macros? Also, is there a library for summarizing differences between s-expressions?