ASP.NET and integration tests - data returned from WebApplicationFactory is nulled when parsed as JSON

Question

I have a problem with integration test (made with WebApplicationFactory) that cannot parse back to JSON obtained response. I have seen some similar issues reported here but nothing found so far was helpful.

Generally, for the test purpose there is this very simple Program.cs:

using System.Text.Json.Serialization;
using Microsoft.AspNetCore.Http.Json;

var builder = WebApplication.CreateBuilder(args);

builder.Services
    .AddControllers();

builder.Services.Configure<JsonOptions>(options =>
{
    options.SerializerOptions.Converters.Add(new JsonStringEnumConverter());
});

var app = builder.Build();

app.MapControllers();

app.MapGet("/test", () => new SomeView { Name = "SomeName", SomeEnum = SomeEnum.No });

app.Run();

public class SomeView
{
    public string Name { get; set; }
    public SomeEnum SomeEnum { get; set; }
}

public enum SomeEnum
{
    Yes = 1,
    No
}

And the following very simple test:

public class UnitTest
{
    [Fact]
    public async Task Test1()
    {
        var factory = new WebApplicationFactory<Program>();
        var client = factory.CreateClient();

        var response = await client.GetAsync("/test");
        var result = await response.Content.ReadFromJsonAsync<SomeView>(new JsonSerializerOptions()
        {
            Converters = { new JsonStringEnumConverter() }
        });

        Assert.Equal(SomeEnum.No, result.SomeEnum);
    }
}

The issue is - running that test is failed since:

Xunit.Sdk.EqualException
Assert.Equal() Failure
Expected: No
Actual:   0

The whole object have nulled properties. Without providing JsonSerializerOptions the application throws another exception that it is not possible to parse that SomeEnum. However, if I will try to get the response by:

var result = await response.Content.ReadAsStringAsync()

The result is correctly set to the:

{"name":"SomeName","someEnum":"No"}

Any suggestion what is done incorrectly here would be appreciated.

Answer 1

Names of properties in json are in different case compared to the properties of SomeView. Either fix it with JsonPropertyNameAttribute or provide naming policy:

var options = new JsonSerializerOptions()
{
    Converters = { new JsonStringEnumConverter() },
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase
};
var result = await response.Content.ReadFromJsonAsync<SomeView>(options);

Another option is to reuse the web defaults for serializer settings:

var options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
{
    Converters = { new JsonStringEnumConverter() }
};