1 files changed, 33 insertions, 0 deletions
diff --git a/devtools/client/framework/test/browser_toolbox_theme.js b/devtools/client/framework/test/browser_toolbox_theme.js
new file mode 100644
index 0000000000..63d83e8312
--- /dev/null
+++ b/devtools/client/framework/test/browser_toolbox_theme.js
@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const PREF_DEVTOOLS_THEME = "devtools.theme";
+
+registerCleanupFunction(() => {
+  // Set preferences back to their original values
+  Services.prefs.clearUserPref(PREF_DEVTOOLS_THEME);
+});
+
+add_task(async function testDevtoolsTheme() {
+  info("Checking stylesheet and :root attributes based on devtools theme.");
+  Services.prefs.setCharPref(PREF_DEVTOOLS_THEME, "light");
+  is(
+    document.getElementById("appcontent").getAttribute("devtoolstheme"),
+    "light",
+    "The element has an attribute based on devtools theme."
+  );
+
+  Services.prefs.setCharPref(PREF_DEVTOOLS_THEME, "dark");
+  is(
+    document.getElementById("appcontent").getAttribute("devtoolstheme"),
+    "dark",
+    "The element has an attribute based on devtools theme."
+  );
+
+  Services.prefs.setCharPref(PREF_DEVTOOLS_THEME, "unknown");
+  is(
+    document.getElementById("appcontent").getAttribute("devtoolstheme"),
+    "light",
+    "The element has 'light' as a default for the devtoolstheme attribute."
+  );
+});