Get Access Token from Azure AD for Integration Testing

AuthHelpers.cs

using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Newtonsoft.Json.Linq;

namespace Api.Test
{
    public static class AuthHelpers
    {
        public static async Task<string> GetAccessToken()
        {
            var configuration = new ConfigurationBuilder()
                .AddUserSecrets<Startup>()
                .AddEnvironmentVariables()
                .Build();

            using (var client = new HttpClient())
            {
                var values = new List<KeyValuePair<string, string>>
                {
                    new KeyValuePair<string, string>("client_id", configuration["Testing:client_id"]),
                    new KeyValuePair<string, string>("client_secret", configuration["Testing:client_secret"]),
                    new KeyValuePair<string, string>("resource", configuration["Testing:resource"]),
                    new KeyValuePair<string, string>("grant_type", "client_credentials")
                };
                var response = await client.PostAsync($"https://login.microsoftonline.com/{configuration["Testing:tenant_id"]}/oauth2/token", new FormUrlEncodedContent(values));
                var parsedObject = JObject.Parse(await response.Content.ReadAsStringAsync());
                return (string)(parsedObject["access_token"]);
            }
        }
    }
}