really basic test runner

npm test now does... something somewhat useful.

now to write a bunch of tests.

.gitignore

@@ -0,0 +1 @@
+node_modules

package.json

@@ -1,11 +1,19 @@
 {
   "name": "jsxm",
-  "version": "1",
+  "version": "1.0.0",
+  "description": "WebAudio FastTracker 2 .XM module player",
+  "keywords": "fasttracker xm webaudio",
+  "uri": "http://www.a1k0n.net/code/jsxm/",
+  "repository": "a1k0n/jsxm",
+  "author": "Andy Sloane <andy@a1k0n.net> (http://www.a1k0n.net/)",
+
   "main": "index.html",
   "window": {
     "frame": true,
     "toolbar": false,
     "position": "center",
     "resizable": true
-  }
+  },
+  "scripts": { "test": "node test/all.js" },
+  "devDependencies": { "test": ">=0.0.5" }
 }

test/all.js

@@ -0,0 +1,82 @@
+window = {};
+
+require('../xm.js', window);
+require('../xmeffects.js', window);
+
+var XMPlayer = window.XMPlayer;
+
+// set up basic blank single-channel, single-pattern XM
+function ResetXMData() {
+  var xm = {};
+  window.XMPlayer.xm = xm;
+  xm.channelinfo = [];
+  xm.songname = "test song";
+  xm.song_looppos = 0;
+  xm.nchan = 1;
+  xm.flags = 1;
+  xm.tempo = 3;
+  xm.bpm = 125;
+  xm.channelinfo.push({
+    number: 0,
+    filterstate: new Float32Array(3),
+    vol: 0,
+    pan: 128,
+    period: 1920 - 48*16,
+    vL: 0, vR: 0,
+    vLprev: 0, vRprev: 0,
+    mute: 0,
+    volE: 0, panE: 0,
+    retrig: 0,
+    vibratodepth: 1,
+    vibratospeed: 1,
+  });
+  xm.songpats = [0];
+  // 1 channel, 2 row blank pattern
+  xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]];
+  xm.instruments = [];
+  xm.instruments.push({
+    'name': "test instrument",
+    'number': 0,
+    'samples': [
+      { 'len': 256, 'loop': 0,
+        'looplen': 256, 'note': 0, 'fine': 0,
+        'pan': 128, 'type': 0, 'vol': 64,
+        'sampledata': new Float32Array(256)
+      }
+    ],
+    'samplemap': new Uint8Array(96),
+    'env_vol': new XMPlayer.Envelope([0, 64, 1, 0], 2, 0, 0, 0),
+    'env_pan': new XMPlayer.Envelope([0, 32], 0, 0, 0, 0)
+  });
+  // reset song position
+  XMPlayer.cur_songpos = -1;
+  XMPlayer.cur_pat = -1;
+  XMPlayer.cur_tick = xm.tempo;
+  return xm;
+}
+
+// using assert passed to the test function that just logs failures 
+exports['test XM startup'] = function(assert) {
+  ResetXMData();
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'advance to initial song position');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  assert.equal(XMPlayer.cur_tick, 0, 'advance to tick 0');
+  assert.equal(XMPlayer.cur_row, 1, 'advance to row 1');
+};
+
+exports['test note on'] = function(assert) {
+  var xm = ResetXMData();
+  // [row][column][channel]
+  xm.patterns[0][0][0] = [48, 1, 0x10 + 33, 0, 0];  // C-4  1 40 000
+  XMPlayer.nextTick();
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.note, 48, 'set note');
+  assert.equal(ch.period, 1152, 'channel period');
+  assert.equal(ch.vol, 33, 'channel volume');
+  assert.equal(ch.samp, xm.instruments[0].samples[0], 'set sample');
+};
+
+if (module == require.main) require('test').run(exports);

xm.js

@@ -9,7 +9,7 @@ if (!window.XMView) {
 }
 var XMView = window.XMView;
 
-player.PeriodForNote = PeriodForNote;
+player.periodForNote = periodForNote;
 player.prettify_effect = prettify_effect;
 player.initAudio = initAudio;
 player.loadXM = loadXM;
@@ -23,6 +23,10 @@ player.cur_ticksamp = 0;
 player.cur_tick = 6;
 player.xm = {};  // contains all song data
 
+// exposed for testing
+player.nextTick = nextTick;
+player.Envelope = Envelope;
+
 // for pretty-printing notes
 var _note_names = [
   "C-", "C#", "D-", "D#", "E-", "F-",
@@ -30,6 +34,10 @@ var _note_names = [
 
 var f_smp = 44100;  // updated by play callback, default value here
 
+// per-sample exponential moving average for volume changes (to prevent pops
+// and clicks); evaluated every 8 samples
+var popfilter_alpha = 0.9837;
+
 function prettify_note(note) {
   if (note < 0) return "---";
   if (note == 96) return "^^^";
@@ -72,7 +80,7 @@ function getstring(dv, offset, len) {
 
 // Return 2-pole Butterworth lowpass filter coefficients for
 // center frequncy f_c (relative to sampling frequency)
-function FilterCoeffs(f_c) {
+function filterCoeffs(f_c) {
   if (f_c > 0.5) {  // we can't lowpass above the nyquist frequency...
     f_c = 0.5;
   }
@@ -84,24 +92,21 @@ function FilterCoeffs(f_c) {
   return [gain, 2*c, -c*c - s*s];
 }
 
-popfilter = FilterCoeffs(200.0 / 44100.0);
+function updateChannelPeriod(ch, period) {
-popfilter_alpha = 0.9837;
-
-function UpdateChannelPeriod(ch, period) {
   var freq = 8363 * Math.pow(2, (1152.0 - period) / 192.0);
   if (isNaN(freq)) {
     console.log("invalid period!", period);
     return;
   }
   ch.doff = freq / f_smp;
-  ch.filter = FilterCoeffs(ch.doff / 2);
+  ch.filter = filterCoeffs(ch.doff / 2);
 }
 
-function PeriodForNote(ch, note) {
+function periodForNote(ch, note) {
   return 1920 - (note + ch.samp.note)*16 - ch.samp.fine / 8.0;
 }
 
-function next_row() {
+function nextRow() {
   if (player.cur_pat == -1 || player.cur_row >= player.xm.patterns[player.cur_pat].length) {
     player.cur_row = 0;
     player.cur_songpos++;
@@ -196,7 +201,7 @@ function next_row() {
     // special handling for portamentos: don't trigger the note
     if (ch.effect == 3 || ch.effect == 5) {
       if (r[i][0] != -1) {
-        ch.periodtarget = PeriodForNote(ch, ch.note);
+        ch.periodtarget = periodForNote(ch, ch.note);
       }
       triggernote = false;
       if (inst && inst.samplemap) {
@@ -224,7 +229,7 @@ function next_row() {
       ch.env_vol = new EnvelopeFollower(inst.env_vol);
       ch.env_pan = new EnvelopeFollower(inst.env_pan);
       if (ch.note != undefined) {
-        ch.period = PeriodForNote(ch, ch.note);
+        ch.period = periodForNote(ch, ch.note);
       }
     }
   }
@@ -279,11 +284,11 @@ EnvelopeFollower.prototype.Tick = function(release) {
   return value;
 };
 
-function next_tick() {
+function nextTick() {
   player.cur_tick++;
   if (player.cur_tick >= player.xm.tempo) {
     player.cur_tick = 0;
-    next_row();
+    nextRow();
   }
   for (var j = 0; j < player.xm.nchan; j++) {
     var ch = player.xm.channelinfo[j];
@@ -305,7 +310,7 @@ function next_tick() {
     }
     ch.volE = ch.env_vol.Tick(ch.release);
     ch.panE = ch.env_pan.Tick(ch.release);
-    UpdateChannelPeriod(ch, ch.period + ch.periodoffset);
+    updateChannelPeriod(ch, ch.period + ch.periodoffset);
   }
 }
 
@@ -386,7 +391,7 @@ function MixChannelIntoBuf(ch, start, end, dataL, dataR) {
   var i = start;
   var failsafe = 100;
   while (i < end) {
-    if (failsafe-- == 0) {
+    if (failsafe-- === 0) {
       console.log("failsafe in mixing loop! channel", ch.number, k, sample_end,
           loopstart, looplen, dk);
       break;
@@ -518,7 +523,7 @@ function audio_cb(e) {
 
   while(buflen > 0) {
     if (player.cur_pat == -1 || player.cur_ticksamp >= ticklen) {
-      next_tick(f_smp);
+      nextTick(f_smp);
       player.cur_ticksamp -= ticklen;
     }
     var tickduration = Math.min(buflen, ticklen - player.cur_ticksamp);

xmeffects.js

@@ -8,7 +8,7 @@ function eff_t1_0(ch) {  // arpeggio
   if (ch.effectdata != 0 && ch.inst != undefined) {
     var arpeggio = [0, ch.effectdata>>4, ch.effectdata&15];
     var note = ch.note + arpeggio[player.cur_tick % 3];
-    ch.period = player.PeriodForNote(ch, note);
+    ch.period = player.periodForNote(ch, note);
   }
 }
 
@@ -294,4 +294,4 @@ player.effects_t1 = [  // effect functions on tick 1+
   eff_unimplemented   // z
 ];
 
-})(window || {});
+})(window);