diff --git a/src/vs/code/electron-main/env.ts b/src/vs/code/electron-main/env.ts
index 58f6359b1a41f5b2db40a4de5877cf0a29fb5a98..76ac4cd52a2a69f61ed40d817babb59ba6764ac9 100644
--- a/src/vs/code/electron-main/env.ts
+++ b/src/vs/code/electron-main/env.ts
@@ -32,7 +32,6 @@ export const IEnvService = createDecorator<IEnvService>('mainEnvironmentService'
 export interface IEnvService {
 	_serviceBrand: any;
 	cliArgs: ICommandLineArguments;
-	isTestingFromCli: boolean;
 	isBuilt: boolean;
 	product: IProductConfiguration;
 	updateUrl: string;
@@ -56,9 +55,6 @@ export class EnvService implements IEnvService {
 	private _userExtensionsHome: string;
 	get userExtensionsHome(): string { return this._userExtensionsHome; }
 
-	private _isTestingFromCli: boolean;
-	get isTestingFromCli(): boolean { return this._isTestingFromCli; }
-
 	get isBuilt(): boolean { return !process.env['VSCODE_DEV']; }
 
 	get product(): IProductConfiguration { return product; }
@@ -129,7 +125,6 @@ export class EnvService implements IEnvService {
 			wait: argv.wait
 		});
 
-		this._isTestingFromCli = this.cliArgs.extensionTestsPath && !this.cliArgs.debugBrkPluginHost;
 		this._userHome = path.join(os.homedir(), product.dataFolderName);
 		this._userExtensionsHome = this.cliArgs.extensionHomePath || path.join(this._userHome, 'extensions');
 	}
diff --git a/src/vs/code/electron-main/main.ts b/src/vs/code/electron-main/main.ts
index 712ee91cba1e80f3c3997480dac94956c8038d4d..0ed34dea755d01091932d2f9d2ca6d6f33b93b50 100644
--- a/src/vs/code/electron-main/main.ts
+++ b/src/vs/code/electron-main/main.ts
@@ -229,7 +229,7 @@ function setupIPC(accessor: ServicesAccessor): TPromise<Server> {
 				client => {
 
 					// Tests from CLI require to be the only instance currently (TODO@Ben support multiple instances and output)
-					if (envService.isTestingFromCli) {
+					if (environmentService.extensionTestsPath && !environmentService.debugExtensionHost.break) {
 						const msg = 'Running extension tests from the command line is currently only supported if no other instance of Code is running.';
 						console.error(msg);
 						client.dispose();