diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..4b818f2
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,20 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        clairnote: ["sn", "dn"]
+        lilypond: ["2-24", "2-25"]
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+      - run: CLAIRNOTE=${{ matrix.clairnote }} ./scripts/test.py -o out -l "$(nix build .#lilypond-${{ matrix.lilypond }} --quiet --no-link --print-out-paths)/bin/lilypond"
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..bf5933d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.pdf
+*.midi
diff --git a/clairnote.ly b/clairnote.ly
index 09f3c2b..6e99381 100644
--- a/clairnote.ly
+++ b/clairnote.ly
@@ -27,88 +27,14 @@
 % For docstrings we use ;; instead of the usual "" to allow automated
 % minification for LilyBin + Clairnote.
 
-%--- UTILITY FUNCTIONS ----------------
-
-#(define (non-zero? n) (not (zero? n)))
-
-#(define (positive-integer? n) (and (positive? n) (integer? n)))
-
-#(define (map-pair proc pair)
-   (cons
-    (proc (car pair))
-    (proc (cdr pair))))
-
-#(define (cn-pitch-to-semitone pitch)
-   ;; Takes a pitch object and returns a semitone integer that corresponds to
-   ;; the pitch's position on the Clairnote staff. Used for
-   ;; staffLineLayoutFunction. The return value is almost always the semitone
-   ;; returned by (ly:pitch-semitones pitch) except for quarter tone
-   ;; alteration exceptions. 1/4 and 3/4 alterations are quarter tone sharps
-   ;; and their semitone needs to be adjusted down by one.
-   (let
-    ((alteration (ly:pitch-alteration pitch))
-     (semitone (ly:pitch-semitones pitch)))
-    (cond
-     ((= 1/4 alteration) (- semitone 1))
-     ((= 3/4 alteration) (- semitone 1))
-     (else semitone))))
-
-#(define (cn-notehead-pitch grob)
-   ;; Takes a note head grob and returns its pitch.
-   (define event (ly:grob-property grob 'cause))
-   (if (ly:stream-event? event)
-       (ly:event-property event 'pitch)
-       (begin
-        (ly:warning "clairnote.ly cannot access the pitch of a note head grob.  (Are you trying to use the Ambitus_engraver?  It is incompatible with clairnote.ly.)")
-        (ly:make-pitch 0 0 0))))
-
-#(define (cn-notehead-semitone grob)
-   ;; Takes a note head grob and returns its semitone.
-   (cn-pitch-to-semitone (cn-notehead-pitch grob)))
-
-#(define (cn-staff-symbol-property grob prop default)
-   ;; Takes a grob @var{grob}, a symbol @var{prop}, and
-   ;; a @var{default} value. Returns that custom StaffSymbol
-   ;; property or silently falls back to the default value.
-   (define staff-sym (ly:grob-object grob 'staff-symbol))
-   (if (ly:grob? staff-sym)
-       (ly:grob-property staff-sym prop)
-       default))
-
-#(define (cn-get-base-staff-space grob)
-   ;; Takes a grob and returns the custom StaffSymbol property
-   ;; cn-base-staff-space.  Silently falls back to the default of 0.75.
-   (cn-staff-symbol-property grob 'cn-base-staff-space 0.75))
-
-#(define (cn-magnification grob)
-   ;; Return the current magnification (from magnifyStaff, etc.)
-   ;; via a grob's font size.
-   (magstep (ly:grob-property grob 'font-size 0)))
-
-#(define (cn-get-staff-clef-adjust staff-octaves clef-octave-shift)
-   ;; Calculate the amount to vertically adjust the position of the clef,
-   ;; key signature, and time signature, in note-spaces / half-staff-spaces.
-   (+
-    (* 12 clef-octave-shift)
-    (if (odd? staff-octaves)
-        6
-        (if (> staff-octaves 2) 12 0))))
-
-#(define (cn-staff-clef-adjust-from-grob grob)
-   (cn-get-staff-clef-adjust
-    (cn-staff-symbol-property grob 'cn-staff-octaves 2)
-    (cn-staff-symbol-property grob 'cn-clef-shift 0)))
-
-#(define (cn-note-heads-from-grob grob default)
-   ;; Takes a grob like a Stem and returns a list of
-   ;; NoteHead grobs or default.
-   (let* ((heads-array (ly:grob-object grob 'note-heads))
-          (heads-list (if (ly:grob-array? heads-array)
-                          (ly:grob-array->list heads-array)
-                          ;; should never/rarely? happen:
-                          default)))
-     heads-list))
+% https://www.gnu.org/software/guile/manual/html_node/Load-Paths.html
+#(add-to-load-path (dirname (current-filename)))
 
+#(load
+  (string-concatenate
+   (list
+    (dirname (current-filename))
+    "/clairnote/init.scm")))
 
 %--- NOTE HEADS AND STEM ATTACHMENT ----------------
 
@@ -139,7 +65,7 @@
 
 #(define (cn-whole-note-stencil grob white-note)
    ;; Returns default Clairnote whole note stencils.
-   (let ((mag (cn-magnification grob))
+   (let ((mag (cn:magnification grob))
          (wn-path (if white-note
                       cn-whole-note-white-path
                       cn-whole-note-black-path)))
@@ -192,7 +118,7 @@
    ;; http://scripts.sil.org/OFL
    ;; http://www.smufl.org/fonts/
    ;; http://blog.steinberg.net/2013/05/introducing-bravura-music-font/
-   (let ((mag (cn-magnification grob))
+   (let ((mag (cn:magnification grob))
          (nh-path (if white-note
                       cn-note-white-path
                       cn-note-black-path)))
@@ -344,7 +270,7 @@
                         (assoc-ref cn-alterations (cons octave notename)))
                        (cn-extract-alteration alteration-def)))
             (pitch (ly:make-pitch octave notename alter))
-            (semitone (cn-pitch-to-semitone pitch)))
+            (semitone (cn:pitch-to-semitone pitch)))
            (cons semitone alteration-def)))
         accidental-alterations))
 
@@ -435,7 +361,7 @@
      (notename (ly:pitch-notename pitch))
      (octave (ly:pitch-octave pitch))
      (alter (ly:pitch-alteration pitch))
-     (semitone (cn-pitch-to-semitone pitch))
+     (semitone (cn:pitch-to-semitone pitch))
 
      ;; will be #f or (alter barnum . end-moment)
      (from-cn-semi-alterations (assoc-get semitone cn-semi-alterations))
@@ -518,7 +444,7 @@ accidental-styles.none = #'(#t () ())
    (make-engraver
     (acknowledgers
      ((accidental-interface engraver grob source-engraver)
-      (let* ((pitch (cn-notehead-pitch (ly:grob-parent grob Y)))
+      (let* ((pitch (cn:notehead-pitch (ly:grob-parent grob Y)))
              (note (ly:pitch-notename pitch))
              (key-alterations (ly:context-property context 'keyAlterations '()))
              (key-sig-alt (assoc-ref key-alterations note))
@@ -582,7 +508,7 @@ accidental-styles.none = #'(#t () ())
 
 #(define (cn-accidental-grob-callback grob)
    ;; Returns an accidental sign stencil.
-   (let* ((mag (cn-magnification grob))
+   (let* ((mag (cn:magnification grob))
           (alt (accidental-interface::calc-alteration grob))
           (direction (and (= 0 alt)
                           (ly:grob-property grob 'cn-natural-sign-direction)))
@@ -699,12 +625,12 @@ accidental-styles.none = #'(#t () ())
 #(define (cn-draw-keysig grob)
    ;; Draws Clairnote key signature stencils.
    (let*
-    ((base-staff-space (cn-get-base-staff-space grob))
+    ((base-staff-space (cn:get-base-staff-space grob))
      (tonic-pitch (ly:grob-property grob 'cn-tonic))
      ;; number of the tonic (0-6) (C-B)
      (tonic-num (ly:pitch-notename tonic-pitch))
      ;; semitone of tonic (0-11) (C-B)
-     (tonic-semi (modulo (cn-pitch-to-semitone tonic-pitch) 12))
+     (tonic-semi (modulo (cn:pitch-to-semitone tonic-pitch) 12))
 
      (alt-list (ly:grob-property grob 'alteration-alist))
      (alt-count (cn-get-keysig-alt-count alt-list))
@@ -720,7 +646,7 @@ accidental-styles.none = #'(#t () ())
      (base-vert-adj (if (= 0 tonic-semi) tonic-semi (- tonic-semi 12)))
 
      ;; adjust position for odd octave staves and clefs shifted up/down an octave, etc.
-     (staff-clef-adjust (cn-staff-clef-adjust-from-grob grob))
+     (staff-clef-adjust (cn:staff-clef-adjust-from-grob grob))
      (vert-adj (* note-space (+ base-vert-adj staff-clef-adjust)))
      (stack (ly:stencil-translate-axis raw-stack vert-adj Y)))
 
@@ -741,7 +667,7 @@ accidental-styles.none = #'(#t () ())
    (if (grob::has-interface grob 'key-cancellation-interface)
        #f
        (let ((stil (cn-draw-keysig grob))
-             (mag (cn-magnification grob)))
+             (mag (cn:magnification grob)))
          (ly:stencil-scale stil mag mag))))
 
 #(define (Cn_key_signature_engraver context)
@@ -943,7 +869,7 @@ accidental-styles.none = #'(#t () ())
              ;; up 6 note-positions for odd octave staves
              ;; up 12 for even octave staves with 4 or more octaves
              ;; up or down 12 * Staff.cnClefShift
-             ((clef-adjust (cn-get-staff-clef-adjust
+             ((clef-adjust (cn:get-staff-clef-adjust
                             (ly:context-property context 'cnStaffOctaves)
                             (ly:context-property context 'cnClefShift))))
 
@@ -1104,15 +1030,15 @@ accidental-styles.none = #'(#t () ())
      (if curve-path
          (let*
           ((curve-stil (make-path-stencil curve-path 0.0001 1 1 #t))
-           (mag (cn-magnification grob))
+           (mag (cn:magnification grob))
            (scaled-curve (ly:stencil-scale curve-stil mag mag))
 
            (transpo (ly:grob-property grob 'cn-clef-transposition))
            ;; bass clef default octave is 3, treble and alto are 4
            (default-octave (if (string=? "clefs.F" glyph) 3 4))
            (octave (+ default-octave (/ transpo 12)))
-           (number-shift (map-pair (lambda (x) (* x mag))
-                                   (cn-clef-number-shift glyph octave)))
+           (number-shift (cn:map-pair (lambda (x) (* x mag))
+                                      (cn-clef-number-shift glyph octave)))
            (scale 0.9)
            (number-stil (ly:stencil-translate
                          (ly:stencil-scale
@@ -1186,19 +1112,19 @@ accidental-styles.none = #'(#t () ())
 #(define (cn-time-signature-grob-callback grob)
    ;; Adjust vertical position of time sig based on vertical staff scaling.
    (let*
-    ((base-staff-space (cn-get-base-staff-space grob))
+    ((base-staff-space (cn:get-base-staff-space grob))
      (vscale-staff (* 12/7 base-staff-space))
      (base-y-offset (* (+ vscale-staff -0.9) -2.5))
 
      ;; adjust position for odd octave staves and clefs shifted up/down an octave
      ;; note-space is the distance between two adjacent notes given vertical staff compression
      (note-space (* 0.5 base-staff-space))
-     (staff-clef-adjust (cn-staff-clef-adjust-from-grob grob))
+     (staff-clef-adjust (cn:staff-clef-adjust-from-grob grob))
 
      (y-offset (+ base-y-offset (* note-space staff-clef-adjust)))
 
      ;; adjustment for \magnifyStaff
-     (mag (cn-magnification grob))
+     (mag (cn:magnification grob))
      (final-y-offset (* y-offset mag)))
 
     (ly:grob-set-property! grob 'Y-offset final-y-offset)))
@@ -1263,7 +1189,7 @@ accidental-styles.none = #'(#t () ())
      ;; --- Y / length ---
 
      (stem-y-extent (ly:grob-property grob 'Y-extent))
-     (note-heads (cn-note-heads-from-grob grob '()))
+     (note-heads (cn:note-heads-from-grob grob '()))
      (heads-edge (cn-grobs-edge note-heads up-stem))
      (stem-tip (if up-stem (cdr stem-y-extent) (car stem-y-extent)))
 
@@ -1300,7 +1226,7 @@ accidental-styles.none = #'(#t () ())
 #(define (cn-customize-stem grob double-stems)
    ;; Lengthen all stems to undo staff compression side effects,
    ;; and give half notes double stems.
-   (let* ((bss-inverse (/ 1 (cn-get-base-staff-space grob)))
+   (let* ((bss-inverse (/ 1 (cn:get-base-staff-space grob)))
           (deets (ly:grob-property grob 'details))
           (deets2 (cn-multiply-details deets bss-inverse '(stem-shorten))))
 
@@ -1368,7 +1294,7 @@ accidental-styles.none = #'(#t () ())
                   ;; START CLAIRNOTE EDITS
 
                   ;; we just get the 1st notehead, does it matter which?
-                  (note-head (list-ref (cn-note-heads-from-grob root '()) 0)))
+                  (note-head (list-ref (cn:note-heads-from-grob root '()) 0)))
 
              ;; if is half note...
              (if (and note-head (= 1 (ly:grob-property note-head 'duration-log)))
@@ -1437,7 +1363,7 @@ accidental-styles.none = #'(#t () ())
 %--- DOTS ON DOTTED NOTES ----------------
 
 #(define (cn-highest-semitone note-heads)
-   (reduce max -inf.0 (map cn-notehead-semitone note-heads)))
+   (reduce max -inf.0 (map cn:notehead-semitone note-heads)))
 
 #(define (cn-make-dots-callback is-rhythmic-staff)
    ;; Avoid collision between double-stem and dots by shifting right the dots
@@ -1459,7 +1385,7 @@ accidental-styles.none = #'(#t () ())
            (= 1 (ly:grob-property note-head 'duration-log))
 
            ;; is line note?
-           (begin (set! semi (cn-notehead-semitone note-head))
+           (begin (set! semi (cn:notehead-semitone note-head))
              (or (= 0 (modulo semi 4)) is-rhythmic-staff))
 
            ;; is up-stem?
@@ -1469,7 +1395,7 @@ accidental-styles.none = #'(#t () ())
            (= 1 (ly:grob-property stem 'direction))
 
            ;; is highest note?
-           (let* ((note-heads (cn-note-heads-from-grob stem '())))
+           (let* ((note-heads (cn:note-heads-from-grob stem '())))
              (or (= 1 (length note-heads))
                  (= semi (cn-highest-semitone note-heads))))
 
@@ -1489,7 +1415,7 @@ accidental-styles.none = #'(#t () ())
 #(define (cn-beam-grob-callback grob)
    ;; Adjust size and spacing of beams.
    ;; Needed due to vertically compressed staff.
-   (let* ((bss-inverse (/ 1 (cn-get-base-staff-space grob)))
+   (let* ((bss-inverse (/ 1 (cn:get-base-staff-space grob)))
           (thick (ly:grob-property grob 'beam-thickness))
           (len-frac (ly:grob-property grob 'length-fraction))
           (space (if (number? len-frac) len-frac 1)))
@@ -1746,7 +1672,7 @@ accidental-styles.none = #'(#t () ())
 #(define cnUnextendStaffDown #{ \cnStaffExtender ##f 0 -1 #})
 
 #(define cnStaffOctaveSpan
-   (define-music-function (octaves) (positive-integer?)
+   (define-music-function (octaves) (cn:positive-integer?)
      ;; odd octaves: extended the same amount up and down (from 1)
      ;; even octaves: extended up one more than they are down
      (let*
@@ -1903,8 +1829,8 @@ accidental-styles.none = #'(#t () ())
 
   ;; Indicates number of octaves the staff spans, lets us use
   ;; different clef settings so stems always flip at center of staff.
-  (context-prop 'cnStaffOctaves positive-integer?)
-  (grob-prop 'cn-staff-octaves positive-integer?)
+  (context-prop 'cnStaffOctaves cn:positive-integer?)
+  (grob-prop 'cn-staff-octaves cn:positive-integer?)
 
   ;; For moving clef position up or down by one or more octaves.
   (context-prop 'cnClefShift integer?)
@@ -1927,7 +1853,7 @@ accidental-styles.none = #'(#t () ())
 
   ;; For Stem grobs, for double stems for half notes.
   (grob-prop 'cn-double-stem-spacing number?)
-  (grob-prop 'cn-double-stem-width-scale non-zero?)
+  (grob-prop 'cn-double-stem-width-scale cn:non-zero?)
 
   ;; Used to produce ledger line pattern.
   (grob-prop 'cn-ledger-recipe list?)
@@ -1981,7 +1907,7 @@ clairnoteTypeUrl = ""
     clefTransposition = 0
     middleCPosition = -12
 
-    staffLineLayoutFunction = #cn-pitch-to-semitone
+    staffLineLayoutFunction = #cn:pitch-to-semitone
 
     printKeyCancellation = ##f
     \numericTimeSignature
@@ -2072,7 +1998,7 @@ initClairnoteDN =
 #(define-scheme-function () ()
    (set! cn-white-note?
          (lambda (grob)
-           (odd? (cn-notehead-semitone grob))))
+           (odd? (cn:notehead-semitone grob))))
 
    (set! cn-default-note-head-stencil-callback
          (cn-make-note-head-stencil-callback
diff --git a/clairnote/init.scm b/clairnote/init.scm
new file mode 100644
index 0000000..babc48b
--- /dev/null
+++ b/clairnote/init.scm
@@ -0,0 +1,39 @@
+(use-modules
+  (srfi srfi-1)
+  (srfi srfi-13)
+  (lily))
+
+;; for me (on guix) %compile-fallback-path is set to a non writable directory.
+;; change it so that it is writable
+;; TODO: other platforms
+(unless (and (access? %compile-fallback-path W_OK) (file-is-directory? %compile-fallback-path))
+  (set! %compile-fallback-path
+    (string-append (getenv "HOME")
+      "/.cache/guile/ccache/lilypond/")))
+
+;; compiled code is faster and have debug info
+(set! %load-should-auto-compile #t)
+(ly:set-option 'compile-scheme-code #t)
+
+;; backtraces are nice
+(debug-enable 'backtrace)
+
+(let ((guile-user-mod (resolve-module '(guile-user))))
+
+  (unless (module-variable guile-user-mod 'cn:clairnote-module-list)
+    (module-define! guile-user-mod
+      'cn:clairnote-module-list
+      (map (lambda (x)
+            (resolve-interface x #:prefix 'cn:))
+        '((clairnote utils)))))
+
+  (map
+    (lambda (x)
+      ;; different from module-add!
+      ;; module-add! allows a var to be used by a module
+      ;; ly:module-copy makes vars available in anything that imports a module
+      ;; so this allows
+      ;; 1) cn:xyz be used in a scope such as \paper
+      ;; 2) lilypond a.ly b.ly to work with clairnote
+      (ly:module-copy (current-module) x))
+    (module-ref guile-user-mod 'cn:clairnote-module-list)))
diff --git a/clairnote/utils.scm b/clairnote/utils.scm
new file mode 100644
index 0000000..a40c82b
--- /dev/null
+++ b/clairnote/utils.scm
@@ -0,0 +1,86 @@
+(define-module (clairnote utils))
+
+(use-modules
+  (srfi srfi-1)
+  (srfi srfi-13)
+  (lily))
+
+(define-public (non-zero? n) (not (zero? n)))
+
+(define-public (positive-integer? n) (and (positive? n) (integer? n)))
+
+(define-public (map-pair proc pair)
+  (cons
+    (proc (car pair))
+    (proc (cdr pair))))
+
+(define-public (pitch-to-semitone pitch)
+  ;; Takes a pitch object and returns a semitone integer that corresponds to
+  ;; the pitch's position on the Clairnote staff. Used for
+  ;; staffLineLayoutFunction. The return value is almost always the semitone
+  ;; returned by (ly:pitch-semitones pitch) except for quarter tone
+  ;; alteration exceptions. 1/4 and 3/4 alterations are quarter tone sharps
+  ;; and their semitone needs to be adjusted down by one.
+  (let
+    ((alteration (ly:pitch-alteration pitch))
+      (semitone (ly:pitch-semitones pitch)))
+    (cond
+      ((= 1/4 alteration) (- semitone 1))
+      ((= 3/4 alteration) (- semitone 1))
+      (else semitone))))
+
+(define-public (notehead-pitch grob)
+  ;; Takes a note head grob and returns its pitch.
+  (define event (ly:grob-property grob 'cause))
+  (if (ly:stream-event? event)
+    (ly:event-property event 'pitch)
+    (begin
+      (ly:warning "clairnote.ly cannot access the pitch of a note head grob.  (Are you trying to use the Ambitus_engraver?  It is incompatible with clairnote.ly.)")
+      (ly:make-pitch 0 0 0))))
+
+(define-public (notehead-semitone grob)
+  ;; Takes a note head grob and returns its semitone.
+  (pitch-to-semitone (notehead-pitch grob)))
+
+(define-public (staff-symbol-property grob prop default)
+  ;; Takes a grob @var{grob}, a symbol @var{prop}, and
+  ;; a @var{default} value. Returns that custom StaffSymbol
+  ;; property or silently falls back to the default value.
+  (define staff-sym (ly:grob-object grob 'staff-symbol))
+  (if (ly:grob? staff-sym)
+    (ly:grob-property staff-sym prop)
+    default))
+
+(define-public (get-base-staff-space grob)
+  ;; Takes a grob and returns the custom StaffSymbol property
+  ;; cn-base-staff-space.  Silently falls back to the default of 0.75.
+  (staff-symbol-property grob 'cn-base-staff-space 0.75))
+
+(define-public (magnification grob)
+  ;; Return the current magnification (from magnifyStaff, etc.)
+  ;; via a grob's font size.
+  (magstep (ly:grob-property grob 'font-size 0)))
+
+(define-public (get-staff-clef-adjust staff-octaves clef-octave-shift)
+  ;; Calculate the amount to vertically adjust the position of the clef,
+  ;; key signature, and time signature, in note-spaces / half-staff-spaces.
+  (+
+    (* 12 clef-octave-shift)
+    (if (odd? staff-octaves)
+      6
+      (if (> staff-octaves 2) 12 0))))
+
+(define-public (staff-clef-adjust-from-grob grob)
+  (get-staff-clef-adjust
+    (staff-symbol-property grob 'cn-staff-octaves 2)
+    (staff-symbol-property grob 'cn-clef-shift 0)))
+
+(define-public (note-heads-from-grob grob default)
+  ;; Takes a grob like a Stem and returns a list of
+  ;; NoteHead grobs or default.
+  (let* ((heads-array (ly:grob-object grob 'note-heads))
+         (heads-list (if (ly:grob-array? heads-array)
+                      (ly:grob-array->list heads-array)
+                      ;; should never/rarely? happen:
+                      default)))
+    heads-list))
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..1bd5a1f
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,96 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1694529238,
+        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
+        "type": "github"
+      },
+      "original": {
+        "id": "flake-utils",
+        "type": "indirect"
+      }
+    },
+    "lilypond-2-24": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1721474473,
+        "narHash": "sha256-CvbVQUXE0rbU8599YA76CB8xmf1cxwwIm8ZywyLKHfY=",
+        "owner": "lilypond",
+        "repo": "lilypond",
+        "rev": "b7908403efe0761cec86c94db0c529db031246a0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "lilypond",
+        "ref": "v2.24.4",
+        "repo": "lilypond",
+        "type": "github"
+      }
+    },
+    "lilypond-2-25": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1720954141,
+        "narHash": "sha256-haiVEMeeIggUQjGJ6i0zj20JEn5VW1tPOrTlwDsmQaQ=",
+        "owner": "lilypond",
+        "repo": "lilypond",
+        "rev": "f1777509159e606513829c6794ec57782b7cacd9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "lilypond",
+        "ref": "v2.25.18",
+        "repo": "lilypond",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1722141560,
+        "narHash": "sha256-Ul3rIdesWaiW56PS/Ak3UlJdkwBrD4UcagCmXZR9Z7Y=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "038fb464fcfa79b4f08131b07f2d8c9a6bcc4160",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "lilypond-2-24": "lilypond-2-24",
+        "lilypond-2-25": "lilypond-2-25",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..18f20a5
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,37 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "flake-utils";
+
+    lilypond-2-24 = {
+      url = "github:lilypond/lilypond/v2.24.4";
+      flake = false;
+    };
+    lilypond-2-25 = {
+      url = "github:lilypond/lilypond/v2.25.18";
+      flake = false;
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+    lilypond-2-24,
+    lilypond-2-25,
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in {
+        packages.lilypond-2-24 = pkgs.lilypond.overrideAttrs {
+          version = "2.24.4";
+          src = lilypond-2-24;
+        };
+        packages.lilypond-2-25 = pkgs.lilypond.overrideAttrs {
+          version = "2.25.18";
+          src = lilypond-2-25;
+        };
+      }
+    );
+}
diff --git a/scripts/test.py b/scripts/test.py
new file mode 100755
index 0000000..91ebd65
--- /dev/null
+++ b/scripts/test.py
@@ -0,0 +1,214 @@
+#!/bin/env python3
+
+import argparse
+import asyncio
+import multiprocessing
+import os
+import shutil
+import tempfile
+from asyncio.subprocess import Process
+from pathlib import Path
+
+
+# https://stackoverflow.com/questions/287871/how-do-i-print-colored-text-to-the-terminal
+class bcolors:
+    HEADER = "\033[95m"
+    OKBLUE = "\033[94m"
+    OKCYAN = "\033[96m"
+    OKGREEN = "\033[92m"
+    WARNING = "\033[93m"
+    FAIL = "\033[91m"
+    ENDC = "\033[0m"
+    BOLD = "\033[1m"
+    UNDERLINE = "\033[4m"
+
+
+output_func_queue = asyncio.Queue()
+fails = []
+
+
+async def run_queue_in_seq():
+    while True:
+        item = await output_func_queue.get()
+        if item is None:
+            return
+        await item()
+
+
+async def run_one_test(file: Path, outpath: Path, process: Process):
+
+    async def show_stdout():
+        stdout = process.stdout
+        assert stdout is not None
+        aggr = []
+        async for line in stdout:
+            aggr.append(line)
+            print(f"{file.name}>> {line.decode(errors='replace')}", end="")
+        return b"".join(aggr)
+
+    async def show_stderr():
+        stderr = process.stderr
+        assert stderr is not None
+        aggr = []
+        async for line in stderr:
+            aggr.append(line)
+            print(f"{file.name}> {line.decode(errors='replace')}", end="")
+        return b"".join(aggr)
+
+    msgs_list = []
+
+    async def wait_one():
+        code, out, err = await asyncio.gather(
+            process.wait(), show_stdout(), show_stderr()
+        )
+        print()
+        for x in msgs_list:
+            print(x)
+        if not code == 0:
+            fails.append(str(file))
+            print(f"{bcolors.FAIL}{file.name}: Failed with code {code}{bcolors.ENDC}")
+            if out:
+                outpath.with_suffix(".stdout").write_bytes(out)
+            if err:
+                outpath.with_suffix(".stderr").write_bytes(err)
+            print()
+
+    await output_func_queue.put(wait_one)
+    try:
+        await asyncio.wait_for(process.wait(), timeout=30)
+    except asyncio.TimeoutError:
+        msgs_list.append(
+            f"{bcolors.FAIL}{file.name}: terminating due to timeout{bcolors.ENDC}"
+        )
+        process.terminate()
+        await asyncio.sleep(1)
+        if process.returncode is None:
+            msgs_list.append(f"{bcolors.FAIL}{file.name}: killing{bcolors.ENDC}")
+            process.kill()
+
+
+async def main():
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument("files", nargs="*")
+    parser.add_argument("-l", "--lilypond", type=str, default=shutil.which("lilypond"))
+    parser.add_argument("-o", "--out", type=str, required=True)
+    parser.add_argument("-i", "--include", type=str, action="append", default=[])
+    parser.add_argument("--cpu", type=int, default=multiprocessing.cpu_count())
+
+    args = parser.parse_args()
+
+    lily_bin = Path(args.lilypond).absolute()
+    assert lily_bin.exists()
+    print(f"using {lily_bin}")
+
+    if args.files:
+        args_files = [Path(x).resolve() for x in sorted(args.files)]
+    else:
+        args_files = [Path(__file__).parent.parent / "test" / "tests"]
+
+    seen = set()
+
+    def walk(p: Path):
+        p = p.resolve()
+        if p not in seen:
+            seen.add(p)
+            if p.is_dir():
+                for c in p.iterdir():
+                    yield from walk(c)
+            elif p.suffix == ".ly":
+                yield p
+
+    files: list[tuple[Path, Path]] = []
+    out_subdirs = set()
+    for file in args_files:
+        for x in walk(file):
+            rel = x.relative_to(file)
+            assert not ".." in rel.parts
+            if rel in out_subdirs:
+                raise RuntimeError(f"conflicting output: {rel}")
+            out_subdirs.add(rel)
+            files.append((x, rel))
+
+    files = sorted(files)
+
+    print(f"running {len(files)} tests")
+
+    ly_args = [
+        "-I",
+        str(Path(__file__).parent),
+    ]
+    includes = args.include
+
+    if len(includes) > 1:
+        raise NotImplementedError()
+
+    for x in includes:
+        ly_args.append("-d")
+        ly_args.append(f"include-settings={x}")
+
+    sem = asyncio.Semaphore(args.cpu)
+
+    outpath = Path(args.out).resolve()
+    print(f"outputing to {outpath}")
+    if not outpath.exists():
+        outpath.mkdir(parents=True)
+
+    assert outpath.is_dir()
+
+    with tempfile.TemporaryDirectory() as tmp_dir:
+
+        print(f"using tmp home: {tmp_dir}")
+
+        async def test_one(file: Path, outrel: Path):
+            async with sem:
+                outrel = outpath / outrel.with_suffix("")
+                outrel.parent.mkdir(parents=True, exist_ok=True)
+                proc = await asyncio.create_subprocess_exec(
+                    lily_bin,
+                    "--output",
+                    str(outrel),
+                    *ly_args,
+                    str(file),
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                    cwd="/",
+                    env={
+                        # for fontconfig and guile cache
+                        "HOME": tmp_dir,
+                        "CLAIRNOTE": os.environ.get("CLAIRNOTE") or "default",
+                    },
+                )
+                await run_one_test(file, outrel, proc)
+
+        jobs = []
+        for file, outrel in files:
+            jobs.append(test_one(file, outrel))
+
+        async def run_jobs():
+            await asyncio.gather(*jobs)
+            await output_func_queue.put(None)
+
+        try:
+            await asyncio.gather(run_queue_in_seq(), run_jobs())
+        except KeyboardInterrupt:
+            print("[KeyboardInterrupt]")
+        finally:
+            if fails:
+                print()
+                print(f"{len(fails)} failed:")
+                for f in fails:
+                    print(f)
+                exit(1)
+
+
+loop = asyncio.new_event_loop()
+asyncio.set_event_loop(loop)
+try:
+    loop.run_until_complete(main())
+except KeyboardInterrupt:
+    tasks = [t for t in asyncio.all_tasks(loop) if not t.done()]
+    [task.cancel() for task in tasks]
+    loop.run_until_complete(asyncio.gather(*tasks, return_exceptions=True))
+finally:
+    loop.close()
diff --git a/test/test-includes.ly b/test/test-includes.ly
index 2b80ce8..4bd1d8d 100644
--- a/test/test-includes.ly
+++ b/test/test-includes.ly
@@ -1,11 +1,16 @@
 \version "2.19.63"
 
-% clairnote-type = dn
+#(define clairnote-type (or (getenv "CLAIRNOTE") "default"))
+
+% supress the version error
+#(define version-seen #t)
+
+#(debug-set! width 200)
 
 \include "../clairnote.ly"
 
 #(set-default-paper-size "a4landscape")
- 
+
 \paper {
   indent = 0
 }
diff --git a/test/tests/rests-in-voices.ly b/test/tests/rests-in-voices.ly
index dbddd2a..4ca4b2e 100644
--- a/test/tests/rests-in-voices.ly
+++ b/test/tests/rests-in-voices.ly
@@ -1,6 +1,6 @@
 \version "2.22.2"
 % clairnote-type = "dn"
-\include "clairnote.ly"
+\include "../test-includes.ly"
 \language "english"
 #(set-default-paper-size "letter")