1 files changed, 22 insertions, 0 deletions
diff --git a/comm/mail/base/test/unit/test_devtools_url.js b/comm/mail/base/test/unit/test_devtools_url.js
new file mode 100644
index 0000000000..d0c8baf21f
--- /dev/null
+++ b/comm/mail/base/test/unit/test_devtools_url.js
@@ -0,0 +1,22 @@
+/**
+ * This test checks for the URL of the developer tools toolbox. If it fails,
+ * then the code for opening the toolbox has likely changed, and the code in
+ * MailGlue that observes command-line-startup will not be working properly.
+ */
+
+Cu.importGlobalProperties(["fetch"]);
+var { MailGlue } = ChromeUtils.import("resource:///modules/MailGlue.jsm");
+
+add_task(async () => {
+  let expectedURL = `"${MailGlue.BROWSER_TOOLBOX_WINDOW_URL}"`;
+  let containingFile =
+    "resource://devtools/client/framework/browser-toolbox/Launcher.sys.mjs";
+
+  let response = await fetch(containingFile);
+  let text = await response.text();
+
+  Assert.ok(
+    text.includes(expectedURL),
+    `Expected to find ${expectedURL} in ${containingFile}.`
+  );
+});