1 files changed, 167 insertions, 0 deletions
diff --git a/dom/ipc/tests/test_blob_sliced_from_parent_process.js b/dom/ipc/tests/test_blob_sliced_from_parent_process.js
new file mode 100644
index 0000000000..e196a6986c
--- /dev/null
+++ b/dom/ipc/tests/test_blob_sliced_from_parent_process.js
@@ -0,0 +1,167 @@
+"use strict";
+
+const { XPCShellContentUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/XPCShellContentUtils.sys.mjs"
+);
+
+XPCShellContentUtils.init(this);
+
+function childFrameScript() {
+  /* eslint-env mozilla/frame-script */
+  const messageName = "test:blob-slice-test";
+  const blobData = ["So", " ", "many", " ", "blobs!"];
+  const blobText = blobData.join("");
+  const blobType = "text/plain";
+
+  const sliceText = "an";
+
+  function info(msg) {
+    sendAsyncMessage(messageName, { op: "info", msg });
+  }
+
+  function ok(condition, name, diag) {
+    sendAsyncMessage(messageName, { op: "ok", condition, name, diag });
+  }
+
+  function is(a, b, name) {
+    let pass = a == b;
+    let diag = pass ? "" : "got " + a + ", expected " + b;
+    ok(pass, name, diag);
+  }
+
+  function finish(result) {
+    sendAsyncMessage(messageName, { op: "done", result });
+  }
+
+  function grabAndContinue(arg) {
+    testGenerator.next(arg);
+  }
+
+  function* testSteps() {
+    addMessageListener(messageName, grabAndContinue);
+    let message = yield undefined;
+
+    let blob = message.data;
+
+    ok(Blob.isInstance(blob), "Received a Blob");
+    is(blob.size, blobText.length, "Blob has correct length");
+    is(blob.type, blobType, "Blob has correct type");
+
+    info("Reading blob");
+
+    let reader = new FileReader();
+    reader.addEventListener("load", grabAndContinue);
+    reader.readAsText(blob);
+
+    yield undefined;
+
+    is(reader.result, blobText, "Blob has correct data");
+
+    let firstSliceStart = blobData[0].length + blobData[1].length;
+    let firstSliceEnd = firstSliceStart + blobData[2].length;
+
+    let slice = blob.slice(firstSliceStart, firstSliceEnd, blobType);
+
+    ok(Blob.isInstance(slice), "Slice returned a Blob");
+    is(slice.size, blobData[2].length, "Slice has correct length");
+    is(slice.type, blobType, "Slice has correct type");
+
+    info("Reading slice");
+
+    reader = new FileReader();
+    reader.addEventListener("load", grabAndContinue);
+    reader.readAsText(slice);
+
+    yield undefined;
+
+    is(reader.result, blobData[2], "Slice has correct data");
+
+    let secondSliceStart = blobData[2].indexOf("a");
+    let secondSliceEnd = secondSliceStart + sliceText.length;
+
+    slice = slice.slice(secondSliceStart, secondSliceEnd, blobType);
+
+    ok(Blob.isInstance(slice), "Second slice returned a Blob");
+    is(slice.size, sliceText.length, "Second slice has correct length");
+    is(slice.type, blobType, "Second slice has correct type");
+
+    info("Sending second slice");
+    finish(slice);
+  }
+
+  let testGenerator = testSteps();
+  testGenerator.next();
+}
+
+add_task(async function test() {
+  let page = await XPCShellContentUtils.loadContentPage(
+    "data:text/html,<!DOCTYPE HTML><html><body></body></html>",
+    {
+      remote: true,
+    }
+  );
+
+  page.loadFrameScript(childFrameScript);
+
+  const messageName = "test:blob-slice-test";
+  const blobData = ["So", " ", "many", " ", "blobs!"];
+  const blobType = "text/plain";
+
+  const sliceText = "an";
+
+  await new Promise(resolve => {
+    function grabAndContinue(arg) {
+      testGenerator.next(arg);
+    }
+
+    function* testSteps() {
+      let slice = yield undefined;
+
+      ok(Blob.isInstance(slice), "Received a Blob");
+      equal(slice.size, sliceText.length, "Slice has correct size");
+      equal(slice.type, blobType, "Slice has correct type");
+
+      let reader = new FileReader();
+      reader.onload = grabAndContinue;
+      reader.readAsText(slice);
+      yield undefined;
+
+      equal(reader.result, sliceText, "Slice has correct data");
+      resolve();
+    }
+
+    let testGenerator = testSteps();
+    testGenerator.next();
+
+    let mm = page.browser.messageManager;
+    mm.addMessageListener(messageName, function (message) {
+      let data = message.data;
+      switch (data.op) {
+        case "info": {
+          info(data.msg);
+          break;
+        }
+
+        case "ok": {
+          ok(data.condition, data.name + " - " + data.diag);
+          break;
+        }
+
+        case "done": {
+          testGenerator.next(data.result);
+          break;
+        }
+
+        default: {
+          ok(false, "Unknown op: " + data.op);
+          resolve();
+        }
+      }
+    });
+
+    let blob = new Blob(blobData, { type: blobType });
+    mm.sendAsyncMessage(messageName, blob);
+  });
+
+  await page.close();
+});