1 files changed, 64 insertions, 0 deletions
diff --git a/toolkit/components/extensions/test/browser/browser_ext_themes_persistence.js b/toolkit/components/extensions/test/browser/browser_ext_themes_persistence.js
new file mode 100644
index 0000000000..526c3a0883
--- /dev/null
+++ b/toolkit/components/extensions/test/browser/browser_ext_themes_persistence.js
@@ -0,0 +1,64 @@
+"use strict";
+
+// This test checks whether applied WebExtension themes are persisted and applied
+// on newly opened windows.
+
+add_task(async function test_multiple_windows() {
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      theme: {
+        images: {
+          theme_frame: "image1.png",
+        },
+        colors: {
+          frame: ACCENT_COLOR,
+          tab_background_text: TEXT_COLOR,
+        },
+      },
+    },
+    files: {
+      "image1.png": BACKGROUND,
+    },
+  });
+
+  await extension.startup();
+
+  let docEl = window.document.documentElement;
+  let toolbox = document.querySelector("#navigator-toolbox");
+  let computedStyle = window.getComputedStyle(
+    backgroundColorSetOnRoot() ? docEl : toolbox
+  );
+
+  Assert.ok(docEl.hasAttribute("lwtheme"), "LWT attribute should be set");
+  Assert.equal(
+    docEl.getAttribute("lwtheme-brighttext"),
+    "true",
+    "LWT text color attribute should be set"
+  );
+  Assert.ok(
+    computedStyle.backgroundImage.includes("image1.png"),
+    "Expected background image"
+  );
+
+  // Now we'll open a new window to see if the theme is also applied there.
+  let window2 = await BrowserTestUtils.openNewBrowserWindow();
+  docEl = window2.document.documentElement;
+  toolbox = window2.document.querySelector("#navigator-toolbox");
+  computedStyle = window.getComputedStyle(
+    backgroundColorSetOnRoot() ? docEl : toolbox
+  );
+
+  Assert.ok(docEl.hasAttribute("lwtheme"), "LWT attribute should be set");
+  Assert.equal(
+    docEl.getAttribute("lwtheme-brighttext"),
+    "true",
+    "LWT text color attribute should be set"
+  );
+  Assert.ok(
+    computedStyle.backgroundImage.includes("image1.png"),
+    "Expected background image"
+  );
+
+  await BrowserTestUtils.closeWindow(window2);
+  await extension.unload();
+});