1 files changed, 53 insertions, 0 deletions
diff --git a/docshell/test/browser/browser_browsingContext-getAllBrowsingContextsInSubtree.js b/docshell/test/browser/browser_browsingContext-getAllBrowsingContextsInSubtree.js
new file mode 100644
index 0000000000..1aba3c00aa
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+++ b/docshell/test/browser/browser_browsingContext-getAllBrowsingContextsInSubtree.js
@@ -0,0 +1,53 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+async function addFrame(url) {
+  let iframe = content.document.createElement("iframe");
+  await new Promise(resolve => {
+    iframe.addEventListener("load", resolve, { once: true });
+    iframe.src = url;
+    content.document.body.appendChild(iframe);
+  });
+  return iframe.browsingContext;
+}
+
+add_task(async function() {
+  await BrowserTestUtils.withNewTab(
+    { gBrowser, url: "about:blank" },
+    async browser => {
+      // Add 15 example.com frames to the toplevel document.
+      let frames = await Promise.all(
+        Array.from({ length: 15 }).map(_ =>
+          // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+          SpecialPowers.spawn(browser, ["http://example.com/"], addFrame)
+        )
+      );
+
+      // Add an example.org subframe to each example.com frame.
+      let subframes = await Promise.all(
+        Array.from({ length: 15 }).map((_, i) =>
+          // eslint-disable-next-line @microsoft/sdl/no-insecure-url
+          SpecialPowers.spawn(frames[i], ["http://example.org/"], addFrame)
+        )
+      );
+
+      Assert.deepEqual(
+        subframes[0].getAllBrowsingContextsInSubtree(),
+        [subframes[0]],
+        "Childless context only has self in subtree"
+      );
+      Assert.deepEqual(
+        frames[0].getAllBrowsingContextsInSubtree(),
+        [frames[0], subframes[0]],
+        "Single-child context has 2 contexts in subtree"
+      );
+      Assert.deepEqual(
+        browser.browsingContext.getAllBrowsingContextsInSubtree(),
+        [browser.browsingContext, ...frames, ...subframes],
+        "Toplevel context has all subtree contexts"
+      );
+    }
+  );
+});