diff --git a/test/authorization-code.ts b/test/authorization-code.ts
index 4bfba5b..ff13dd0 100644
--- a/test/authorization-code.ts
+++ b/test/authorization-code.ts
@@ -10,9 +10,9 @@ const codeChallenge = 'E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM';
 describe('authorization-code', () => {
   let server: ReturnType<typeof testServer>;
 
-  after(() => {
+  after(async () => {
     if (server) {
-      server.close();
+      await server.close();
     }
   });
 
diff --git a/test/client-credentials.ts b/test/client-credentials.ts
index 7706526..3041349 100644
--- a/test/client-credentials.ts
+++ b/test/client-credentials.ts
@@ -6,9 +6,9 @@ import { after, describe, it } from 'node:test';
 describe('client-credentials', () => {
   let server: ReturnType<typeof testServer>;
 
-  after(() => {
+  after(async () => {
     if (server) {
-      server.close();
+      await server.close();
     }
 
   });
diff --git a/test/password.ts b/test/password.ts
index 6810b63..f29afa5 100644
--- a/test/password.ts
+++ b/test/password.ts
@@ -6,9 +6,9 @@ import { after, describe, it } from 'node:test';
 describe('password', () => {
   let server: ReturnType<typeof testServer>;
 
-  after(() => {
+  after(async () => {
     if (server) {
-      server.close();
+      await server.close();
     }
   });
 
diff --git a/test/revoke.ts b/test/revoke.ts
index 7ce961d..02fa46b 100644
--- a/test/revoke.ts
+++ b/test/revoke.ts
@@ -6,9 +6,9 @@ import { after, describe, it } from 'node:test';
 describe('Token revocation', () => {
   const server = testServer();
 
-  after(() => {
+  after(async () => {
     if (server) {
-      server.close();
+      await server.close();
     }
   });
 
diff --git a/test/test-server.ts b/test/test-server.ts
index 2ed52fd..484f61d 100644
--- a/test/test-server.ts
+++ b/test/test-server.ts
@@ -56,7 +56,7 @@ export function testServer() {
 
 const oauth2Error: Middleware = (ctx, next) => {
 
-  if (ctx.request.body.client_id !== 'oauth2-error') {
+  if (ctx.request.body?.client_id !== 'oauth2-error') {
     return next();
   }
 
@@ -72,7 +72,7 @@ const oauth2Error: Middleware = (ctx, next) => {
 };
 const jsonError: Middleware = (ctx, next) => {
 
-  if (ctx.request.body.client_id !== 'json-error') {
+  if (ctx.request.body?.client_id !== 'json-error') {
     return next();
   }
 
@@ -88,7 +88,7 @@ const jsonError: Middleware = (ctx, next) => {
 };
 const generalHttpError: Middleware = (ctx, next) => {
 
-  if (ctx.request.body.client_id !== 'general-http-error') {
+  if (ctx.request.body?.client_id !== 'general-http-error') {
     return next();
   }