Integration Testing - Microservice calling each other

I'm having trouble with running integration test on my application.

I'm trying to write a test on controller that calls another api controller in same solution.

So basicly i have two APIS one calling other in same solution.

I know how to test one API but i can't seem to figure out how to run the other API.

I have tried building two seperate TestServers with different startup. But nothing seems to trigger other api.

Any pointers will be deeply appreciated.

    [TestInitialize]
    public void Init()
    {
        var builder = new WebHostBuilder()
            .UseConfiguration(new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .Build())
            .UseStartup<Startup>();
        _server = new TestServer(builder);
        _client = _server.CreateClient();
    }


    [TestMethod]
    public void TestUser()
    {
        var request = _client.GetAsync("/api/v1/").Result;
        var jsonString = request.Content.ReadAsStringAsync().Result;
        var result = JsonConvert.DeserializeObject<bool>(jsonString);
        Assert.IsNotNull(result);
    }




    public async Task<bool?> GetUser()
    {
        bool? result = null;
        HttpResponseMessage response = await _client.GetAsync("/");
        if (response.IsSuccessStatusCode)
        {
            var responseContent = await response.Content.ReadAsStringAsync();
            result = JsonConvert.DeserializeObject<bool>(responseContent);
        }
        return result;

    }