Add test for SymbolBucket#isEmpty being false if bucket has rtl text

test/unit/data/symbol_bucket.test.js

@@ -97,6 +97,18 @@ test('SymbolBucket detects rtl text', (t) => {
     t.end();
 });
 
+// Test to prevent symbol bucket with rtl from text being culled by worker serialization.
+test('SymbolBucket with rtl text is NOT empty even though no symbol instances are created', (t) => {
+    const rtlBucket = bucketSetup('مرحبا');
+    const options = {iconDependencies: {}, glyphDependencies: {}};
+    rtlBucket.createArrays();
+    rtlBucket.populate([{feature}], options);
+
+    t.notOk(rtlBucket.isEmpty());
+    t.equal(rtlBucket.symbolInstances.length, 0);
+    t.end();
+});
+
 test('SymbolBucket detects rtl text mixed with ltr text', (t) => {
     const mixedBucket = bucketSetup('مرحبا translates to hello');
     const options = {iconDependencies: {}, glyphDependencies: {}};

test/unit/source/tile.test.js

@@ -267,7 +267,9 @@ test('expiring tiles', (t) => {
 test('rtl text detection', (t) => {
     t.test('Tile#hasRTLText is true when a tile loads a symbol bucket with rtl text', (t) => {
         const tile = new Tile(new OverscaledTileID(1, 0, 1, 1, 1));
-        const symbolBucket = createSymbolBucket('test', 'Test', 'مرحبا', new CollisionBoxArray());
+        // Create a stub symbol bucket
+        const symbolBucket = createSymbolBucket('test', 'Test', 'test', new CollisionBoxArray());
+        // symbolBucket phasnt been populateed yet so we force override the value in the stub
         symbolBucket.hasRTLText = true;
         tile.loadVectorData(
             createVectorData({rawTileData: createRawTileData(), buckets: [symbolBucket]}),