1 files changed, 73 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..01dfbf893e
--- /dev/null
+++ b/dom/webgpu/mochitest/test_buffer_mapping.html
@@ -0,0 +1,73 @@
+<!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>