Imagine that I have the following files in my (ridiculous) package:

File test1.el:

;;; test1.el ---                                   

;;; Code:

(defvar test-var1)

(defun test-fun1 (test)
  nil)

(require 'test2 "./test2.el)

(provide 'test1)
;;; test1.el ends here

File test2.el:

;;; test2.el ---  

;;; Code:

(defun test-fun2 ()
  (let ((test test-var1))
    (test-fun1 test)))

(provide 'test2)
;;; test2.el ends here

If then I run:

emacs -batch -f batch-byte-compile *.el

I get the following result:

Compiling .../test1.el...
Wrote .../test1.elc
Compiling .../test2.el...

In test-fun2:
test2.el:9:15:Warning: reference to free variable `test-var1'

In end of data:
test2.el:14:1:Warning: the function `test-fun1' is not known to be defined.
Wrote .../test2.elc

I understand why these warnings appear, and I understand that they are only warnings. However, it would be easy to miss a typo in a function name by dismissing all warnings of this kind.

I somehow thought that adding a (require 'test2) line in test2.el should fix it. However, in this case I get:

Compiling .../test1.el...

In toplevel form:
test1.el:10:1:Error: Recursive `require' for feature `test2'
Compiling .../test2.el...

In toplevel form:
test2.el:5:1:Error: Recursive `require' for feature `test1'

This is cryptic, because I thought that the point of require was precisely to avoid recursive loading. I assume that require is behaving like load during compilation time.

What is a good (and safe) way to get rid of these warnings?

The manual gives a work-around (I post it as a better-than-nothing answer below), but ultimately, I'd like the solution to be rather automatic (not requiring me to list all functions and variables that I will need in every file).

The ideal solution would be built-in in emacs or provided with Cask. If it doesn't exist, I will take what is available of course.