Update pattern filtering logic and add faderPattern test case

src/lib/transformers/ableton.ts

@@ -378,7 +378,7 @@ function abletonTransformer(data: ProjectRawData, exporterParams: ExporterParams
     data.groupPatterns
       .filter(
         (pattern) =>
-          pattern.events.length > 0 &&
+          getPatternSources(pattern).length > 0 &&
           !referencedPatterns.has(getPatternKey(pattern.group, pattern.patternNumber)),
       )
       .toSorted((a, b) => {

tests/ableton-song.test.ts

@@ -80,6 +80,30 @@ function pattern(
   };
 }
 
+function faderPattern(group: Group, patternNumber: number): GroupPattern {
+  return {
+    group,
+    patternNumber,
+    bars: 1,
+    recordCount: 1,
+    events: [
+      {
+        type: 'fader',
+        kind: PatternEventKind.Fader,
+        position: 0,
+        source: 0,
+        flags: 0,
+        rawData: new Uint8Array(8),
+        parameter: FaderParam.LPF,
+        reserved: 0,
+        rawValue: 0,
+        value: 0,
+      },
+    ],
+    notes: {},
+  };
+}
+
 function scene(
   number: number,
   patternNumbers: Record<Group, number>,
@@ -111,6 +135,7 @@ function project(): ProjectRawData {
       pattern('a', 3, 1, 1, 64),
       pattern('c', 3, 1, 0, 67),
       pattern('b', 1, 1, 0, 38),
+      faderPattern('d', 2),
     ],
     scenes: [
       scene(1, { a: 1, b: 2, c: 0, d: 0 }, 3, 4),