chore: CM-1300 Test DB Connection In Health Check (#854)

backend/src/app.controller.spec.ts

@@ -1,17 +1,22 @@
 import { Test, TestingModule } from "@nestjs/testing";
 import { AppController } from "./app.controller";
 import { AppService } from "./app.service";
-import { JwtAuthGuard } from "./auth/jwtauth.guard";
-import { JwtRoleGuard } from "./auth/jwtrole.guard";
-import { ROUTE_ARGS_METADATA } from "@nestjs/common/constants";
+import { DataSource } from "typeorm";
+import { dataSourceMockFactory } from "../test/mocks/datasource";
 
 describe("AppController", () => {
   let appController: AppController;
 
   beforeEach(async () => {
     const app: TestingModule = await Test.createTestingModule({
       controllers: [AppController],
-      providers: [AppService],
+      providers: [
+        AppService,
+        {
+          provide: DataSource,
+          useFactory: dataSourceMockFactory,
+        },
+      ],
     }).compile();
 
     appController = app.get<AppController>(AppController);

backend/src/app.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Get, UseGuards } from "@nestjs/common";
+import { Controller, Get, HttpException } from "@nestjs/common";
 import { AppService } from "./app.service";
 import { ApiTags } from "@nestjs/swagger";
 import { Public } from "./auth/decorators/public.decorator";
@@ -10,12 +10,15 @@ export class AppController {
 
   @Get()
   @Public()
-  getHello(): string {
-    return this.appService.getHello();
+  async getDBHealthCheck(): Promise<string> {
+    const result = await this.appService.getDBHealthCheck();
+    if (result === "Success") {
+      return Promise.resolve(result);
+    } else throw new HttpException("Unable to connect to database", 503);
   }
 
   @Get()
-  getHelloPrivate(): string {
+  getHello(): string {
     return this.appService.getHello();
   }
 }

backend/src/app.service.ts

@@ -1,8 +1,20 @@
 import { Injectable } from "@nestjs/common";
+import { DataSource } from "typeorm";
 
 @Injectable()
 export class AppService {
+  constructor(private readonly dataSource: DataSource) {}
   getHello(): string {
     return "Hello Backend!";
   }
+
+  // return Success if able to Select 1 from database
+  async getDBHealthCheck(): Promise<string> {
+    try {
+      await this.dataSource.query("SELECT 1");
+      return "Success";
+    } catch (error) {
+      return "Failure";
+    }
+  }
 }