anchor.diff:    `(let ((,backend (ernestine-database:get-backend :prevalence "/tmp/foo/")))
        ,@body))
   
  +(defun generate-random-name (token)
  +  (format nil "~A-~A" token (gensym)))
  +
   (define-test add-artist
     (with-prevalence-backend (backend)
  -    (let* ((name (format nil "artist-~A" (gensym)))
  +    (let* ((name (generate-random-name "artist"))
   	   (data (ernestine-database:make-artist backend name nil)))
         (assert-true (eq (type-of data) 'ernestine-database:artist)))))
   
   (define-test delete-artist
     (with-prevalence-backend (backend)
  -    (let* ((name (format nil "artist-~A" (gensym))))
  +    (let* ((name (generate-random-name "artist")))
         (ernestine-database:make-artist backend name nil)
         (assert-true (ernestine-database:delete-artist backend name)))))
   
   (define-test cant-add-existing-artist
     (with-prevalence-backend (backend)
  -    (let* ((name (format nil "artist-~A" (gensym))))
  +    (let* ((name (generate-random-name "artist")))
         (ernestine-database:make-artist backend name nil)
         (assert-error 'ernestine-database:existing-artist-error
   		    (ernestine-database:make-artist backend name nil)))))
   
   (define-test delete-unknown-artist
     (with-prevalence-backend (backend)
  -    (let* ((name (format nil "artist-~A" (gensym))))
  +    (let* ((name (generate-random-name "artist")))
         (assert-error 'ernestine-database:unknown-artist-error
   		    (ernestine-database:delete-artist backend name)))))
   
   (define-test add-album
     (with-prevalence-backend (backend)
  -    (let* ((artist-name (format nil "artist-~A" (gensym)))
  -	   (album-name (format nil "album-~A" (gensym))))
  +    (let* ((artist-name (generate-random-name "artist"))
  +	   (album-name (generate-random-name "album")))
         (ernestine-database:make-artist backend artist-name nil)
         (let ((data (ernestine-database:make-album backend
   						 artist-name
  
positive.code: 
  (define-test delete-song
    (with-prevalence-backend (backend)
      (let* ((artist-name (format nil "artist-~A" (gensym)))
  	   (album-name (format nil "album-~A" (gensym)))
  	   (song-name (format nil "song-~A" (gensym))))
        (ernestine-database:make-artist backend artist-name nil)
        (ernestine-database:make-album backend
  				     artist-name
  
negative.code: 
  (define-test cant-add-existing-album
    (with-prevalence-backend (backend)
      (let* ((artist-name (generate-random-name "artist"))
  	   (album-name (generate-random-name "album")))
        (ernestine-database:make-artist backend artist-name nil)
        (ernestine-database:make-album backend
  				     artist-name
  