test: GET endpoints should respond to HEAD reqs

integration/hello-world/e2e/express-instance.spec.ts

@@ -45,6 +45,10 @@ describe('Hello world (express instance)', () => {
     });
   });
 
+  it('/HEAD should respond to with a 200', () => {
+    return request(server).head('/hello').expect(200);
+  });
+
   afterEach(async () => {
     await app.close();
   });

integration/hello-world/e2e/fastify-adapter.spec.ts

@@ -87,6 +87,15 @@ describe('Hello world (fastify adapter)', () => {
       .then(({ payload }) => expect(payload).to.be.eql('Hello world!'));
   });
 
+  it('/HEAD should respond to with a 200', () => {
+    return app
+      .inject({
+        method: 'HEAD',
+        url: '/hello',
+      })
+      .then(({ statusCode }) => expect(statusCode).to.be.eq(200));
+  });
+
   afterEach(async () => {
     await app.close();
   });

packages/platform-fastify/adapters/fastify-adapter.ts

@@ -682,7 +682,10 @@ export class FastifyAdapter<
     return rawRequest.originalUrl || rawRequest.url;
   }
 
-  private injectRouteOptions(routerMethodKey: HTTPMethods, ...args: any[]) {
+  private injectRouteOptions(
+    routerMethodKey: Uppercase<HTTPMethods>,
+    ...args: any[]
+  ) {
     const handlerRef = args[args.length - 1];
     const isVersioned =
       !isUndefined(handlerRef.version) &&