1 files changed, 39 insertions, 0 deletions
diff --git a/dom/webgpu/tests/cts/checkout/src/webgpu/api/operation/buffers/mapping_test.ts b/dom/webgpu/tests/cts/checkout/src/webgpu/api/operation/buffers/mapping_test.ts
new file mode 100644
index 0000000000..733e2dcb69
--- /dev/null
+++ b/dom/webgpu/tests/cts/checkout/src/webgpu/api/operation/buffers/mapping_test.ts
@@ -0,0 +1,39 @@
+import { assert } from '../../../../common/util/util.js';
+import { GPUTest } from '../../../gpu_test.js';
+
+export class MappingTest extends GPUTest {
+  checkMapWrite(
+    buffer: GPUBuffer,
+    offset: number,
+    mappedContents: ArrayBuffer,
+    size: number
+  ): void {
+    this.checkMapWriteZeroed(mappedContents, size);
+
+    const mappedView = new Uint32Array(mappedContents);
+    const expected = new Uint32Array(new ArrayBuffer(size));
+    assert(mappedView.byteLength === size);
+    for (let i = 0; i < mappedView.length; ++i) {
+      mappedView[i] = expected[i] = i + 1;
+    }
+    buffer.unmap();
+
+    this.expectGPUBufferValuesEqual(buffer, expected, offset);
+  }
+
+  checkMapWriteZeroed(arrayBuffer: ArrayBuffer, expectedSize: number): void {
+    this.expect(arrayBuffer.byteLength === expectedSize);
+    const view = new Uint8Array(arrayBuffer);
+    this.expectZero(view);
+  }
+
+  expectZero(actual: Uint8Array): void {
+    const size = actual.byteLength;
+    for (let i = 0; i < size; ++i) {
+      if (actual[i] !== 0) {
+        this.fail(`at [${i}], expected zero, got ${actual[i]}`);
+        break;
+      }
+    }
+  }
+}