diff --git a/.eslintrc.js b/.eslintrc.js
index 6adaf38..f78cb5b 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -6,6 +6,7 @@ module.exports = {
   rules: {
     'func-call-spacing': 'off',
     'space-before-function-paren': 'off',
-    '@typescript-eslint/no-var-requires': 'off'
+    '@typescript-eslint/no-var-requires': 'off',
+    '@typescript-eslint/ban-ts-comment': 'off'
   }
 };
diff --git a/src/OpenAPM.ts b/src/OpenAPM.ts
index eb19a26..22b87fb 100644
--- a/src/OpenAPM.ts
+++ b/src/OpenAPM.ts
@@ -17,9 +17,10 @@ import { getHostIpAddress, getPackageJson, getSanitizedPath } from './utils';
 import { instrumentExpress } from './clients/express';
 import { instrumentMySQL } from './clients/mysql2';
 import { instrumentNestFactory } from './clients/nestjs';
-import { LevitateConfig, LevitateEvents } from './levitate/events';
 import { instrumentNextjs } from './clients/nextjs';
 
+import { LevitateConfig, LevitateEvents } from './levitate/events';
+
 export type ExtractFromParams = {
   from: 'params';
   key: string;
@@ -85,7 +86,7 @@ const moduleNames = {
 const packageJson = getPackageJson();
 
 export class OpenAPM extends LevitateEvents {
-  private simpleCache: Record<string, any> = {};
+  readonly simpleCache: Record<string, any> = {};
   private path: string;
   private metricsServerPort: number;
   private enabled: boolean;
@@ -189,8 +190,6 @@ export class OpenAPM extends LevitateEvents {
         console.log('Shutting down metrics server gracefully.');
       }
       this.metricsServer?.close((err) => {
-        promClient.register.clear();
-
         if (err) {
           reject(err);
           return;
@@ -199,6 +198,9 @@ export class OpenAPM extends LevitateEvents {
         resolve(undefined);
         console.log('Metrics server shut down gracefully.');
       });
+
+      promClient.register.clear();
+      resolve(undefined);
     });
   };
 
@@ -348,6 +350,8 @@ export class OpenAPM extends LevitateEvents {
         const prisma = new PrismaClient();
         const prismaMetrics = prisma ? await prisma.$metrics.prometheus() : '';
         metrics += prisma ? prismaMetrics : '';
+
+        await prisma.$disconnect();
       } catch (error) {
         this.simpleCache['prisma:installed'] = false;
       }
@@ -392,7 +396,6 @@ export class OpenAPM extends LevitateEvents {
       }
     } catch (error) {
       if (Object.keys(moduleNames).includes(moduleName)) {
-        console.log(error);
         throw new Error(
           `OpenAPM couldn't import the ${moduleNames[moduleName]} package, please install it.`
         );
diff --git a/tests/mysql2.test.ts b/tests/mysql2.test.ts
index 0e0b169..5933fbd 100644
--- a/tests/mysql2.test.ts
+++ b/tests/mysql2.test.ts
@@ -1,9 +1,9 @@
-import { describe, beforeAll, expect, test, vi, afterAll } from 'vitest';
-import mysql2, { Connection, Pool, PoolCluster, PoolNamespace } from 'mysql2';
+import { describe, beforeAll, expect, test, afterAll } from 'vitest';
+import mysql2, { Connection, Pool, PoolCluster } from 'mysql2';
 import { instrumentMySQL, symbols } from '../src/clients/mysql2';
 import prom, { Histogram } from 'prom-client';
 
-const connectionUri = `mysql://root@localhost:3306/test_db`;
+const connectionUri = 'mysql://root@localhost:3306/test_db';
 
 const sendTestRequest = async (conn: Connection | Pool, query: string) => {
   return new Promise((resolve) => {
diff --git a/tests/prisma.test.ts b/tests/prisma.test.ts
new file mode 100644
index 0000000..377a83e
--- /dev/null
+++ b/tests/prisma.test.ts
@@ -0,0 +1,44 @@
+import express, { Express } from 'express';
+import { test, expect, describe, beforeAll, afterAll, vi } from 'vitest';
+
+import OpenAPM from '../src/OpenAPM';
+import { addRoutes, makeRequest } from './utils';
+
+describe('Prisma', () => {
+  let openapm: OpenAPM;
+  let app: Express;
+
+  beforeAll(async () => {
+    openapm = new OpenAPM({
+      enableMetricsServer: false
+    });
+    openapm.instrument('express');
+
+    app = express();
+
+    app.get('/metrics', async (req, res) => {
+      res.status(200).send(await openapm.getMetrics());
+    });
+
+    addRoutes(app);
+    app.listen(3002);
+  });
+
+  afterAll(async () => {
+    await openapm.shutdown();
+  });
+
+  test('prisma:installed - false', async () => {
+    vi.doMock('@prisma/client', async () => {
+      throw new Error('Cannot find module @prisma/client');
+    });
+    await makeRequest(app, '/api/10');
+    await makeRequest(app, '/metrics');
+
+    expect(openapm.simpleCache['prisma:installed']).toBe(false);
+  });
+
+  test('simpleCache', async () => {
+    expect(openapm.simpleCache['prisma:installed']).toBe(false);
+  });
+});