C# HTTP test with Json

HttpTest.cs

using System.Text.Json.Nodes;
using System.Xml.Linq;

namespace Test.TestCase;

public class HttpTest
{
    private ApplicationFactory _factory { get; set; }

    private ClientAuth _clientAuth { get; set; }

    private TestDatabase _db { get; set; }

    public HttpTest(
        ApplicationFactory factory,
        ClientAuth clientAuth,
        TestDatabase db
    )
    {
        _db = db;
        _factory = factory;
        _clientAuth = clientAuth;
    }

    [Fact]
    public async Task TestGetCustomers()
    {
        // Arrange
        var client = _factory.CreateClient();
        _clientAuth.AddBasicAuthHeaders(client);

        // Act
        var response = await client.GetAsync("/api/customers");

        // Assert
        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
        Assert.Equal("application/json; charset=utf-8", response.Content.Headers.ContentType?.ToString());
    }

    [Fact]
    public async Task TestPostCustomer()
    {
        // Arrange
        var client = _factory.CreateClient();
        _clientAuth.AddBasicAuthHeaders(client);

        // Act
        var payload = new
        {
            first_name = "Max",
            last_name = "Meier"
        };

        var content = TestJson.Content(payload);
        var response = await client.PostAsync("/api/customers", content);

        // Assert
        Assert.Equal(HttpStatusCode.Created, response.StatusCode);

        var json = await response.Content.ReadAsStringAsync();

        var expected = new
        {
            customer_id = "1",
        };

        JsonAssert.Equal(expected, json);
    }

}

JsonAssert.cs

using System.Text.Json.Nodes;

namespace Test
{
    public static class JsonAssert
    {
        public static void Equal(object expected, string actualJson)
        {
            var expectedNode = JsonSerializer.SerializeToNode(expected);
            var actualNode = JsonNode.Parse(actualJson);

            if (JsonNode.DeepEquals(actualNode, expectedNode))
            {
                return;
            }

            var actualElement = JsonSerializer.Deserialize<object>(actualJson);
            var expectedJson = JsonSerializer.Serialize(expected);
            var expectedElement = JsonSerializer.Deserialize<object>(expectedJson);

            Assert.Equal(expectedElement, actualElement);
        }
    }
}