1 files changed, 82 insertions, 0 deletions
diff --git a/dom/ipc/tests/browser_subframesPreferUsed.js b/dom/ipc/tests/browser_subframesPreferUsed.js
new file mode 100644
index 0000000000..f2f9ed2593
--- /dev/null
+++ b/dom/ipc/tests/browser_subframesPreferUsed.js
@@ -0,0 +1,82 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+ok(
+  Services.appinfo.fissionAutostart,
+  "this test requires fission to function!"
+);
+
+function documentURL(origin, html) {
+  let params = new URLSearchParams();
+  params.append("html", html.trim());
+  return `${origin}/document-builder.sjs?${params.toString()}`;
+}
+
+async function singleTest(preferUsed) {
+  info(`running test with preferUsed=${preferUsed}`);
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["dom.ipc.processCount.webIsolated", 4],
+      ["browser.tabs.remote.subframesPreferUsed", preferUsed],
+    ],
+  });
+
+  const TEST_URL = documentURL(
+    "https://example.com",
+    `<iframe src=${JSON.stringify(
+      documentURL("https://example.org", `<h1>iframe</h1>`)
+    )}></iframe>`
+  );
+
+  await BrowserTestUtils.withNewTab(TEST_URL, async browser1 => {
+    is(browser1.browsingContext.children.length, 1);
+    let topProc1 = browser1.browsingContext.currentWindowGlobal.domProcess;
+    let frameProc1 =
+      browser1.browsingContext.children[0].currentWindowGlobal.domProcess;
+    isnot(
+      topProc1.childID,
+      frameProc1.childID,
+      "the frame should be in a separate process"
+    );
+
+    await BrowserTestUtils.withNewTab(TEST_URL, async browser2 => {
+      is(browser2.browsingContext.children.length, 1);
+      let topProc2 = browser2.browsingContext.currentWindowGlobal.domProcess;
+      let frameProc2 =
+        browser2.browsingContext.children[0].currentWindowGlobal.domProcess;
+      isnot(
+        topProc2.childID,
+        frameProc2.childID,
+        "the frame should be in a separate process"
+      );
+
+      // Compare processes used for the two tabs.
+      isnot(
+        topProc1.childID,
+        topProc2.childID,
+        "the toplevel windows should be loaded in separate processes"
+      );
+      if (preferUsed) {
+        is(
+          frameProc1.childID,
+          frameProc2.childID,
+          "the iframes should load in the same process with subframesPreferUsed"
+        );
+      } else {
+        isnot(
+          frameProc1.childID,
+          frameProc2.childID,
+          "the iframes should load in different processes without subframesPreferUsed"
+        );
+      }
+    });
+  });
+}
+
+add_task(async function test_preferUsed() {
+  await singleTest(true);
+});
+
+add_task(async function test_noPreferUsed() {
+  await singleTest(false);
+});