1 files changed, 59 insertions, 0 deletions
diff --git a/dom/webgpu/mochitest/test_buffer_mapping.html b/dom/webgpu/mochitest/test_buffer_mapping.html
new file mode 100644
index 0000000000..a3f59d0caf
--- /dev/null
+++ b/dom/webgpu/mochitest/test_buffer_mapping.html
@@ -0,0 +1,59 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<meta charset='utf-8'>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<link rel="stylesheet" href="/tests/SimpleTest/test.css">
+</head>
+<body>
+<script>
+
+ok(SpecialPowers.getBoolPref('dom.webgpu.enabled'), 'Pref should be enabled.');
+
+async function testBody() {
+  const adapter = await navigator.gpu.requestAdapter();
+  const device = await adapter.requestDevice();
+
+  const bufferRead = device.createBuffer({ size:4, usage: GPUBufferUsage.MAP_READ | GPUBufferUsage.COPY_DST });
+  const bufferWrite = device.createBuffer({ size:4, usage: GPUBufferUsage.COPY_SRC, mappedAtCreation: true });
+  (new Float32Array(bufferWrite.getMappedRange())).set([1.0]);
+  bufferWrite.unmap();
+
+  const encoder = device.createCommandEncoder();
+  encoder.copyBufferToBuffer(bufferWrite, 0, bufferRead, 0, 4);
+  device.queue.submit([encoder.finish()]);
+
+  await bufferRead.mapAsync(GPUMapMode.READ);
+
+  try {
+    bufferRead.getMappedRange(0, 5);
+    ok(false, 'mapped with size outside buffer should throw');
+  } catch(e) {
+    ok(true, 'mapped with size outside buffer should throw OperationError');
+  }
+
+  try {
+    bufferRead.getMappedRange(4, 1);
+    ok(false, 'mapped with offset outside buffer should throw');
+  } catch(e) {
+    ok(true, 'mapped with offset outside buffer should throw OperationError');
+  }
+
+  const data = bufferRead.getMappedRange();
+  is(data.byteLength, 4, 'array should be 4 bytes long');
+
+  const value = (new Float32Array(data))[0];
+  ok(value == 1.0, 'value == 1.0');
+
+  bufferRead.unmap();
+  is(data.byteLength, 0, 'array should be detached after explicit unmap');
+};
+
+SimpleTest.waitForExplicitFinish();
+testBody()
+  .catch((e) => ok(false, "Unhandled exception " + e))
+  .finally(() => SimpleTest.finish());
+
+</script>
+</body>
+</html>