(defmacro in-test-window (&rest body)
  `(save-selected-window
    (switch-to-buffer-other-window "*kj/test*")
    ,@body))

(macroexpand '(in-test-window (insert "hello") (insert "world")))

(defun setup-test-window ()
  (in-test-window
    (erase-buffer)))

(defun kj-writeln (msg)
  (in-test-window
   (insert (concat msg "\n"))))

(setup-test-window)

(kj-writeln
 (in-test-window
  (insert (propertize "* Emacs tests" 'face 'org-level-1))))

(defmacro kj-display (title &rest code)
  `(progn
     (kj-writeln (propertize (concat "** " ,title) 'face 'org-level-2))
     (kj-writeln (propertize "Code:" 'face 'italic))
     (kj-writeln (format "%s" ',@code))
     (kj-writeln (propertize "Output:" 'face 'italic))
     (kj-writeln (format "%s" ,@code))))

(load-file "hello-world/hello-world.el")
(kj-display "Hello" (hello))

(load-file "two-fer/two-fer.el")
(kj-display "Two-fer" (two-fer "Annie"))

(load-file "leap/leap.el")
(kj-display "* Leap years"
            (leap-year-p 1996))

(provide 'hello)