fix: added additional negative test cases for getApps method. feat: begin writing tests for getAppById method

src/OnspringClient.ts

@@ -73,9 +73,29 @@ export class OnspringClient {
     );
 
     var apiResponse = await this.get<any>(endpoint);
+
+    if (apiResponse.isSuccessful === false) {
+      return apiResponse;
+    }
+
     return apiResponse.AsGetPagedAppsResponseType();
   }
 
+  public async getAppById(appId: number): Promise<ApiResponse<App>> {
+    const endpoint = EndpointFactory.getAppByIdEndpoint(
+      this._client.defaults.baseURL,
+      appId
+    );
+
+    var apiResponse = await this.get<any>(endpoint);
+
+    if (apiResponse.isSuccessful === false) {
+      return apiResponse;
+    }
+
+    return apiResponse.AsAppType();
+  }
+
   /**
    * @method get - Makes a GET request to the specified endpoint.
    * @param {string} endpoint - The endpoint that will be used to make the request.

src/models/ApiResponse.ts

@@ -1,5 +1,5 @@
-import { App } from "./App";
-import { GetPagedAppsResponse } from "./GetPagedAppsResponse";
+import { App } from './App';
+import { GetPagedAppsResponse } from './GetPagedAppsResponse';
 
 /**
  * @class ApiResponse - A generic response object for API requests.
@@ -42,10 +42,10 @@ export class ApiResponse<T> {
   /**
    * @method AsGetPagedAppsResponseType - Converts the ApiResponse to an ApiResponse<GetPagedAppsResponse>.
    * @returns {ApiResponse<GetPagedAppsResponse>} - An ApiResponse<GetPagedAppsResponse>.
-  */
+   */
   public AsGetPagedAppsResponseType(): ApiResponse<GetPagedAppsResponse> {
     var apiResponse = this as ApiResponse<any>;
-    
+
     var apps = apiResponse.data.items.map((item: any) => {
       return new App(item.href, item.id, item.name);
     });
@@ -64,4 +64,20 @@ export class ApiResponse<T> {
       getAppsPagedResponse
     );
   }
+
+  AsAppType(): ApiResponse<App> {
+    var apiResponse = this as ApiResponse<any>;
+
+    var app = new App(
+      apiResponse.data.href,
+      apiResponse.data.id,
+      apiResponse.data.name
+    );
+
+    return new ApiResponse<App>(
+      apiResponse.statusCode,
+      apiResponse.message,
+      app
+    );
+  }
 }