Can I set up an integration testing environment with no app available and no code? If so, how?

     public class TestesIntegracaoUser : IClassFixture<WebApplicationFactory<Program>>
    {
        private readonly WebApplicationFactory<Program> _factory;
        private const string URLBase = "http://User";

        public TestesIntegracaoUser(WebApplicationFactory<Program> factory)
        {
            _factory = factory;
        }
    //Actual test code
}