add custom rule to prevent test.only

build/lib/eslint/code-no-test-only.js

@@ -0,0 +1,17 @@
+"use strict";
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+module.exports = new class NoTestOnly {
+    create(context) {
+        return {
+            ['MemberExpression[object.name="test"][property.name="only"]']: (node) => {
+                return context.report({
+                    node,
+                    message: 'test.only is a dev-time tool and CANNOT be pushed'
+                });
+            }
+        };
+    }
+};