add AbortSignal test

Author: stepankuzmin

test/unit/source/custom_source.test.js

@@ -184,6 +184,24 @@ test('CustomSource', (t) => {
         sourceCache._addTile(tileID);
     });
 
+    t.test('loadTile aborts', (t) => {
+        const tileID = new OverscaledTileID(0, 0, 0, 0, 0);
+
+        const loadTile = t.spy(async (tile, {signal}) => {
+            t.ok(signal, 'AbortSignal is present in loadTile');
+            signal.addEventListener('abort', () => {
+                t.pass('AbortSignal was aborted');
+                t.end();
+            });
+        });
+
+        const {sourceCache} = createSource(t, {loadTile});
+
+        sourceCache.onAdd();
+        const tile = sourceCache._addTile(tileID);
+        sourceCache._abortTile(tile);
+    });
+
     t.test('prepareTile does not change the tile data if it returns undefined', (t) => {
         const tileID = new OverscaledTileID(0, 0, 0, 0, 0);
         const expectedData = new window.ImageData(512, 512);