Test buffer.mapAsync() early rejection

takahirox · takahirox · commit f831bef3327e · 2022-11-25T17:02:53.000-08:00
With this WebGPU spec change gpuweb/gpuweb#3348 buffer.mapAsync() rejects immediately if it is pending map. This commit adds a test to check it.
diff --git a/src/webgpu/api/validation/buffer/mapping.spec.ts b/src/webgpu/api/validation/buffer/mapping.spec.ts
@@ -280,6 +280,39 @@ g.test('mapAsync,offsetAndSizeOOB')
     await t.testMapAsyncCall(success, 'OperationError', buffer, mapMode, offset, size);
   });
 
+g.test('mapAsync,earlyRejection')
+  .desc("Test that mapAsync fails immediately if it's pending map.")
+  .paramsSubcasesOnly(u => u.combine('mapMode', kMapModeOptions).combine('offset2', [0, 8]))
+  .fn(async t => {
+    const { mapMode, offset2 } = t.params;
+
+    const bufferSize = 16;
+    const mapSize = 8;
+    const offset1 = 0;
+
+    const buffer = t.createMappableBuffer(mapMode, bufferSize);
+
+    const p1 = buffer.mapAsync(mapMode, offset1, mapSize); // succeeds
+    let success = false;
+    {
+      let caught = false;
+      // should be already rejected
+      const p2 = buffer.mapAsync(mapMode, offset2, mapSize);
+      // queues a microtask catching the rejection
+      p2.catch(() => {
+        caught = true;
+      });
+      // queues a second microtask to capture the state immediately after the catch.
+      // Test fails if p2 isn't rejected before the second microtask is fired or
+      // p1 is resolved.
+      queueMicrotask(() => {
+        success = caught;
+      });
+    }
+    await p1; // ensure the original map still succeeds
+    assert(success);
+  });
+
 g.test('getMappedRange,state,mapped')
   .desc('Test that it is valid to call getMappedRange in the mapped state')
   .paramsSubcasesOnly(u => u.combine('mapMode', kMapModeOptions))
