bst launch shouldn't require interaction model to run

bin/bst-launch.ts

@@ -52,7 +52,7 @@ program
 
         const speaker = new BSTVirtualAlexa(url, interactionModel, intentSchemaPath, samplesPath, applicationID, locale);
         try {
-            speaker.start();
+            speaker.start(true);
         } catch (error) {
             process.exit(0);
             return;

lib/client/bst-virtual-alexa.ts

@@ -16,6 +16,7 @@ export class BSTVirtualAlexa {
     public static DefaultIntentSchemaLocation = "speechAssets/IntentSchema.json";
     public static DefaultSampleUtterancesLocation = "speechAssets/SampleUtterances.txt";
     public static DefaultInteractionModelLocation = "models/en-US.json";
+    static DefaultInteractionModel = { interactionModel: { languageModel: { invocationName: "", intents: [] }}};
 
     private virtualAlexa: VirtualAlexa = null;
     private interactionModelProvided: boolean = false;
@@ -132,7 +133,7 @@ export class BSTVirtualAlexa {
         }
     }
 
-    private validateFilesAndBuild(): VirtualAlexa {
+    private validateFilesAndBuild(createdEmptyInteractionModelIfNeeded: boolean): VirtualAlexa {
         const builder = VirtualAlexa.Builder().applicationID(this.applicationID).skillURL(this.skillURL);
         let usingInteractionModel = false;
 
@@ -144,11 +145,12 @@ export class BSTVirtualAlexa {
             }
         }
 
+
         if (!(this.interactionModelProvided || this.intentSchemaProvided)) {
             // No model provided, we check if default files exists
             if (fs.existsSync(this.interactionModel)) {
                 usingInteractionModel = true;
-            } else if (!(fs.existsSync(this.intentSchemaFile) && fs.existsSync(this.sampleUtterancesFile))) {
+            } else if (!(fs.existsSync(this.intentSchemaFile) && fs.existsSync(this.sampleUtterancesFile)) && !createdEmptyInteractionModelIfNeeded) {
                 // Model don't exist in default locations
                 console.error("Error loading Interaction model, no file provided and none found in default locations");
                 throw new Error("Error loading Interaction model, no file provided and none found in default locations");
@@ -173,19 +175,20 @@ export class BSTVirtualAlexa {
         if (usingInteractionModel) {
             this.validateJsonFiles(this.interactionModel, BSTVirtualAlexa.FileTypes.InterationModel);
             builder.interactionModelFile(this.interactionModel);
+        } else if (createdEmptyInteractionModelIfNeeded) {
+            builder.interactionModel(BSTVirtualAlexa.DefaultInteractionModel);
         } else {
             this.validateJsonFiles(this.intentSchemaFile, BSTVirtualAlexa.FileTypes.IntentSchema);
             builder.intentSchemaFile(this.intentSchemaFile).sampleUtterancesFile(this.sampleUtterancesFile);
         }
-
         return builder.create();
     }
 
     /**
      * Start the emulator
      */
-    public start(): void {
-        this.virtualAlexa = this.validateFilesAndBuild();
+    public start(createdEmptyInteractionModelIfNeeded?: boolean): void {
+        this.virtualAlexa = this.validateFilesAndBuild(createdEmptyInteractionModelIfNeeded);
     }
 
     /**

test/client/bst-virtual-alexa-test.ts

@@ -92,6 +92,14 @@ describe("BSTVirtualAlexa", async function() {
             process.chdir("../..");
         });
 
+        it("Start with defaults and non english model", function () {
+            process.chdir("test/resources/nonUSModel");
+            const speak = new BSTVirtualAlexa("http://localhost:9000");
+            speak.start(true);
+            assert(true, "Start processed without exceptions");
+            process.chdir("../../..");
+        });
+
         it("Use provided models even when default is present in folder", function () {
             process.chdir("test/resources/allSpeechModels");
             const speak = new BSTVirtualAlexa("http://localhost:9000",