test: cover unknown API routes

src/server.test.ts

@@ -36,4 +36,13 @@ describe("API endpoints", () => {
       },
     });
   });
+
+  it("returns 404 for an unknown endpoint", async () => {
+    const response = await app.inject({
+      method: "GET",
+      url: "/does-not-exist",
+    });
+
+    assert.equal(response.statusCode, 404);
+  });
 });