chore: fix unit tests

Author: Fatme

test/services/playground/preview-app-plugins-service.ts

@@ -4,6 +4,7 @@ import { Device } from "nativescript-preview-sdk";
 import { assert } from "chai";
 import * as util from "util";
 import { PluginComparisonMessages } from "../../../lib/services/livesync/playground/preview-app-constants";
+import { ErrorsStub } from "../../stubs";
 
 let readJsonParams: string[] = [];
 let warnParams: string[] = [];
@@ -43,6 +44,7 @@ function createTestInjector(localPlugins: IStringDictionary, options?: { isNativ
 		trace: () => ({}),
 		warn: (message: string) =>  warnParams.push(message)
 	});
+	injector.register("errors", ErrorsStub);
 	injector.register("previewAppPluginsService", PreviewAppPluginsService);
 	return injector;
 }

test/services/preview-devices-service.ts

@@ -3,14 +3,16 @@ import { PreviewDevicesService } from "../../lib/services/livesync/playground/de
 import { Device } from "nativescript-preview-sdk";
 import { assert } from "chai";
 import { DeviceDiscoveryEventNames } from "../../lib/common/constants";
-import { LoggerStub } from "../stubs";
+import { LoggerStub, ErrorsStub } from "../stubs";
 
 let foundDevices: Device[] = [];
 let lostDevices: Device[] = [];
 
 function createTestInjector(): IInjector {
 	const injector = new Yok();
+	injector.register("errors", ErrorsStub);
 	injector.register("previewDevicesService", PreviewDevicesService);
+	injector.register("previewAppPluginsService", {});
 	injector.register("logger", LoggerStub);
 	return injector;
 }