public async Task GetAuthenticatedWebClientUsingAppOnlyAuthenticationAsync_TenantIdRequired()
        {
            var appId = "appId";

            var clientCertificate = new X509Certificate2(@"Certs\testwebapplication.pfx", "password");

            try
            {
                var client = await BusinessClientExtensions.GetAuthenticatedWebClientUsingAppOnlyAuthenticationAsync(
                    new BusinessAppConfig
                {
                    ActiveDirectoryAppId             = appId,
                    ActiveDirectoryClientCertificate = clientCertificate,
                    ActiveDirectoryServiceResource   = serviceResourceId,
                },
                    serviceResourceId,
                    /* tenantId */ null,
                    this.credentialCache.Object,
                    this.httpProvider.Object);
            }
            catch (OneDriveException exception)
            {
                Assert.AreEqual(OneDriveErrorCode.AuthenticationFailure.ToString(), exception.Error.Code, "Unexpected error thrown.");
                Assert.AreEqual("Tenant ID is required for app-only authentication.", exception.Error.Message, "Unexpected error thrown.");

                throw;
            }
        }
        public async Task GetAuthenticatedWebClientUsingAppOnlyAuthenticationAsync_ClientCertificateRequired()
        {
            var appId  = "appId";
            var siteId = "site_id";
            var tenant = "tenant";

            try
            {
                var client = await BusinessClientExtensions.GetAuthenticatedWebClientUsingAppOnlyAuthenticationAsync(
                    new BusinessAppConfig
                {
                    ActiveDirectoryAppId           = appId,
                    ActiveDirectoryServiceResource = serviceResourceId,
                },
                    siteId,
                    tenant,
                    this.credentialCache.Object,
                    this.httpProvider.Object);
            }
            catch (OneDriveException exception)
            {
                Assert.AreEqual(OneDriveErrorCode.AuthenticationFailure.ToString(), exception.Error.Code, "Unexpected error thrown.");
                Assert.AreEqual("ActiveDirectoryClientCertificate is required for app-only authentication.", exception.Error.Message, "Unexpected error thrown.");

                throw;
            }
        }