refactor: update title controller tests to use async assertion matchers and refine userId type in anilist service.

src/controllers/title/index.spec.ts

@@ -51,7 +51,7 @@ describe('requests the "/title" route', () => {
       headers: new Headers({ "x-anilist-token": "asd" }),
     });
 
-    expect(await response.json()).toMatchSnapshot();
+    await expect(response.json()).resolves.toMatchSnapshot();
     expect(response.status).toBe(200);
   });
 
@@ -63,7 +63,7 @@ describe('requests the "/title" route', () => {
 
     const response = await app.request("/title?id=10");
 
-    expect(await response.json()).toMatchSnapshot();
+    await expect(response.json()).resolves.toMatchSnapshot();
     expect(response.status).toBe(200);
   });
 
@@ -75,7 +75,7 @@ describe('requests the "/title" route', () => {
 
     const response = await app.request("/title?id=-1");
 
-    expect(await response.json()).toEqual({ success: false });
+    await expect(response.json()).resolves.toEqual({ success: false });
     expect(response.status).toBe(404);
   });
 });