Setup test, break apart entrypoint, & align GHA workflow

backend/src/services/health.ts

@@ -0,0 +1,32 @@
+/* eslint-disable no-console */
+import mongoose from 'mongoose';
+import { createTerminus } from '@godaddy/terminus';
+
+export const setUpHealthEndpoint = <T>(server: T) => {
+  const onSignal = () => {
+    console.log('Server is starting clean-up');
+    return Promise.all([
+      () => {
+        if (mongoose.connection && mongoose.connection.readyState == 1) {
+          mongoose.connection.close();
+          () => {
+            console.info('Database connection closed');
+          };
+        }
+      }
+    ]);
+  };
+
+  const healthCheck = () => {
+    // `state.isShuttingDown` (boolean) shows whether the server is shutting down or not
+    // optionally include a resolve value to be included as info in the health check response
+    return Promise.resolve();
+  };
+
+  createTerminus(server, {
+    healthChecks: {
+      '/healthcheck': healthCheck,
+      onSignal
+    }
+  });
+};