1 files changed, 41 insertions, 0 deletions
diff --git a/devtools/client/dom/test/browser_dom_fission_target_switching.js b/devtools/client/dom/test/browser_dom_fission_target_switching.js
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index 0000000000..4393a7d842
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+++ b/devtools/client/dom/test/browser_dom_fission_target_switching.js
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test top-level target switching in the DOM panel.
+
+const PARENT_PROCESS_URI = "about:robots";
+const CONTENT_PROCESS_URI = URL_ROOT_SSL + "page_basic.html";
+
+add_task(async function () {
+  // We use about:robots as the starting page because it will run in the parent process.
+  // Navigating from that page to a regular content page will always trigger a target
+  // switch, with or without fission.
+
+  info("Open a page that runs in the parent process");
+  const { panel } = await addTestTab(PARENT_PROCESS_URI);
+
+  const _aProperty = getRowByLabel(panel, "_a");
+  let buttonProperty = getRowByLabel(panel, "button");
+
+  ok(!_aProperty, "There is no _a property on the about:robots page");
+  ok(buttonProperty, "There is, however, a button property on this page");
+
+  info("Navigate to a page that runs in the content process");
+  // Wait for the DOM panel to refresh.
+  const store = getReduxStoreFromPanel(panel);
+  const onPropertiesFetched = waitForDispatch(store, "FETCH_PROPERTIES");
+  // Also wait for the toolbox to switch to the new target, to avoid hanging requests when
+  // the test ends.
+  await navigateTo(CONTENT_PROCESS_URI);
+  await onPropertiesFetched;
+
+  await waitFor(() => getRowByLabel(panel, "_a"));
+  ok(true, "This time, the _a property exists on this content process page");
+
+  buttonProperty = getRowByLabel(panel, "button");
+  ok(
+    !buttonProperty,
+    "There is, however, no more button property on this page"
+  );
+});