Google.Api.Ads.AdManager.Lib.AdManagerApiException: 'AdManagerApiException: A valid application name was not found in the request header

Question

I am trying to setup XUnit to test my google ad manager api service. When I run the test, I hit this exception.

Google.Api.Ads.AdManager.Lib.AdManagerApiException: 'AdManagerApiException: A valid application name was not found in the request header. Please provide a valid application name by modifying the ApplicationName setting in your application's

This is my constructor which has the issue to configure ApplicationName

I can't find NetworkCode and AuthorizationMethod

public class GoogleAdManagerServiceTest
{
    private readonly GoogleAdManagerService _googleAdManagerService;        
    private readonly AdManagerUser _user;

    public GoogleAdManagerServiceTest()
    {            
        _user = new AdManagerUser();
        _user.Config.ApplicationName = "xxx"; // How to configure ApplicationName because it cannot be found.            
        _user.Config.OAuth2ClientId = "xxx";
        _user.Config.OAuth2ClientSecret = "xxx";
        _user.Config.OAuth2RefreshToken = "xxx";

        _googleAdManagerService = new GoogleAdManagerService(_user);
    }

    [Fact]
    public void TestGetCompanies()
    {
        try
        {
            // Arrange                

            // Act
            
            // Assert
            
        }
        catch (Exception ex)
        {
            Assert.True(false, $"Test failed with exception: {ex.Message}");
        }
    }
}