1 files changed, 80 insertions, 0 deletions
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-observers.js b/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-observers.js
new file mode 100644
index 0000000000..97e578a1f4
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/balanced-observers.js
@@ -0,0 +1,80 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require("../lib/rules/balanced-observers");
+var RuleTester = require("eslint").RuleTester;
+
+const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: "latest" } });
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+function error(code, observable) {
+  return {
+    code,
+    errors: [
+      {
+        messageId: "noCorresponding",
+        type: "Identifier",
+        data: { observable },
+      },
+    ],
+  };
+}
+
+ruleTester.run("balanced-observers", rule, {
+  valid: [
+    "Services.obs.addObserver(observer, 'observable');" +
+      "Services.obs.removeObserver(observer, 'observable');",
+    "Services.prefs.addObserver('preference.name', otherObserver);" +
+      "Services.prefs.removeObserver('preference.name', otherObserver);",
+  ],
+  invalid: [
+    error(
+      // missing Services.obs.removeObserver
+      "Services.obs.addObserver(observer, 'observable');",
+      "observable"
+    ),
+
+    error(
+      // wrong observable name for Services.obs.removeObserver
+      "Services.obs.addObserver(observer, 'observable');" +
+        "Services.obs.removeObserver(observer, 'different-observable');",
+      "observable"
+    ),
+
+    error(
+      // missing Services.prefs.removeObserver
+      "Services.prefs.addObserver('preference.name', otherObserver);",
+      "preference.name"
+    ),
+
+    error(
+      // wrong observable name for Services.prefs.removeObserver
+      "Services.prefs.addObserver('preference.name', otherObserver);" +
+        "Services.prefs.removeObserver('other.preference', otherObserver);",
+      "preference.name"
+    ),
+
+    error(
+      // mismatch Services.prefs vs Services.obs
+      "Services.obs.addObserver(observer, 'observable');" +
+        "Services.prefs.removeObserver(observer, 'observable');",
+      "observable"
+    ),
+
+    error(
+      "Services.prefs.addObserver('preference.name', otherObserver);" +
+        // mismatch Services.prefs vs Services.obs
+        "Services.obs.removeObserver('preference.name', otherObserver);",
+      "preference.name"
+    ),
+  ],
+});