diff --git a/.eslintrc.json b/.eslintrc.json
index ffc218dfa94..fc92f326b7c 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -133,7 +133,9 @@
 				"restrictions": [
 					"vs/nls",
 					"**/vs/base/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -171,7 +173,9 @@
 					"vs/nls",
 					"**/vs/base/{common,node}/**",
 					"**/vs/base/parts/*/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -190,7 +194,9 @@
 					"vs/css!./**/*",
 					"**/vs/base/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/base/parts/*/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -199,7 +205,9 @@
 					"vs/nls",
 					"**/vs/base/{common,node,electron-main}/**",
 					"**/vs/base/parts/*/{common,node,electron-main}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -256,7 +264,9 @@
 					"**/vs/base/{common,node}/**",
 					"**/vs/base/parts/*/{common,node}/**",
 					"**/vs/platform/*/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -277,7 +287,9 @@
 					"**/vs/base/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/base/parts/*/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/platform/*/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -287,7 +299,9 @@
 					"**/vs/base/{common,node,electron-main}/**",
 					"**/vs/base/parts/*/{common,node,electron-main}/**",
 					"**/vs/platform/*/{common,node,electron-main}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -514,7 +528,9 @@
 					"**/vs/workbench/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/api/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/services/*/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -529,7 +545,9 @@
 					"vs/workbench/contrib/files/browser/editors/fileEditorInput",
 					"**/vs/workbench/services/**",
 					"**/vs/workbench/test/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -593,7 +611,9 @@
 					"**/vs/workbench/{common,node}/**",
 					"**/vs/workbench/api/{common,node}/**",
 					"**/vs/workbench/services/**/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -624,7 +644,9 @@
 					"**/vs/workbench/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/api/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/services/**/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -743,7 +765,9 @@
 					"**/vs/workbench/api/{common,node}/**",
 					"**/vs/workbench/services/**/{common,node}/**",
 					"**/vs/workbench/contrib/**/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -776,7 +800,9 @@
 					"**/vs/workbench/api/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/services/**/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/workbench/contrib/**/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -799,7 +825,9 @@
 					"**/vs/base/parts/**/{common,node}/**",
 					"**/vs/platform/**/{common,node}/**",
 					"**/vs/code/**/{common,node}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -811,7 +839,9 @@
 					"**/vs/base/parts/**/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/platform/**/{common,browser,node,electron-sandbox,electron-browser}/**",
 					"**/vs/code/**/{common,browser,node,electron-sandbox,electron-browser}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -822,7 +852,9 @@
 					"**/vs/base/parts/**/{common,node,electron-main}/**",
 					"**/vs/platform/**/{common,node,electron-main}/**",
 					"**/vs/code/**/{common,node,electron-main}/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -834,7 +866,9 @@
 					"**/vs/platform/**/{common,node}/**",
 					"**/vs/workbench/**/{common,node}/**",
 					"**/vs/server/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -905,28 +939,36 @@
 				"target": "**/test/smoke/**",
 				"restrictions": [
 					"**/test/smoke/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
 				"target": "**/test/automation/**",
 				"restrictions": [
 					"**/test/automation/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
 				"target": "**/test/integration/**",
 				"restrictions": [
 					"**/test/integration/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
 				"target": "**/test/monaco/**",
 				"restrictions": [
 					"**/test/monaco/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -944,21 +986,27 @@
 				"target": "**/{node,electron-browser,electron-main}/**/*.test.ts",
 				"restrictions": [
 					"**/vs/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
 				"target": "**/{node,electron-browser,electron-main}/**/test/**",
 				"restrictions": [
 					"**/vs/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
 				"target": "**/test/{node,electron-browser,electron-main}/**",
 				"restrictions": [
 					"**/vs/**",
-					"@vscode/*", "@parcel/*", "*" // node modules
+					"@vscode/*",
+					"@parcel/*",
+					"*" // node modules
 				]
 			},
 			{
@@ -1004,6 +1052,14 @@
 				"jsdoc/no-types": "off"
 			}
 		},
+		{
+			"files": [
+				"**/*.test.ts"
+			],
+			"rules": {
+				"code-no-test-only": "error"
+			}
+		},
 		{
 			"files": [
 				"**/vscode.d.ts",
diff --git a/build/lib/eslint/code-no-test-only.js b/build/lib/eslint/code-no-test-only.js
new file mode 100644
index 00000000000..46d144bfcaf
--- /dev/null
+++ b/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'
+                });
+            }
+        };
+    }
+};
diff --git a/build/lib/eslint/code-no-test-only.ts b/build/lib/eslint/code-no-test-only.ts
new file mode 100644
index 00000000000..a04483ea6ab
--- /dev/null
+++ b/build/lib/eslint/code-no-test-only.ts
@@ -0,0 +1,20 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as eslint from 'eslint';
+
+export = new class NoTestOnly implements eslint.Rule.RuleModule {
+
+	create(context: eslint.Rule.RuleContext): eslint.Rule.RuleListener {
+		return {
+			['MemberExpression[object.name="test"][property.name="only"]']: (node: any) => {
+				return context.report({
+					node,
+					message: 'test.only is a dev-time tool and CANNOT be pushed'
+				});
+			}
+		};
+	}
+};