diff --git a/src/Untappd.Net.UnitTests/Authentication/TestAuthenticationHelper.cs b/src/Untappd.Net.UnitTests/Authentication/TestAuthenticationHelper.cs
new file mode 100644
index 0000000..4d2d1b5
--- /dev/null
+++ b/src/Untappd.Net.UnitTests/Authentication/TestAuthenticationHelper.cs
@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using Untappd.Net.Authentication;
+using Untappd.Net.Client;
+
+namespace Untappd.Net.UnitTests.Authentication
+{
+    [TestFixture]
+    public class TestAuthenticationHelper
+    {
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void TestRedirectUserToException1()
+        {
+
+            AuthenticationHelper.RedirectUserTo(null, "url");
+        }
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void TestRedirectUserToException2()
+        {
+
+            AuthenticationHelper.RedirectUserTo(new UnAuthenticatedUntappdCredentials("d", "d"), string.Empty);
+        }
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void TestTokenUrlException1()
+        {
+
+            AuthenticationHelper.TokenUrl(null, "some", "code");
+        }
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void TestTokenUrlException2()
+        {
+
+            AuthenticationHelper.TokenUrl(new UnAuthenticatedUntappdCredentials("d", "d"), string.Empty, "code");
+        }
+        [Test]
+        [ExpectedException(typeof(ArgumentNullException))]
+        public void TestTokenUrlException3()
+        {
+
+            AuthenticationHelper.TokenUrl(new UnAuthenticatedUntappdCredentials("d", "d"),  "ds", string.Empty);
+        }
+    }
+}
diff --git a/src/Untappd.Net.UnitTests/Untappd.Net.UnitTests.csproj b/src/Untappd.Net.UnitTests/Untappd.Net.UnitTests.csproj
index 0986b69..9530b32 100644
--- a/src/Untappd.Net.UnitTests/Untappd.Net.UnitTests.csproj
+++ b/src/Untappd.Net.UnitTests/Untappd.Net.UnitTests.csproj
@@ -69,6 +69,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Authentication\TestAuthenticationHelper.cs" />
     <Compile Include="Class1.cs" />
     <Compile Include="Client\TestAuthenticatedUntappdCredentials.cs" />
     <Compile Include="Client\TestUnAuthenticatedUntappdCredentials.cs" />
diff --git a/src/Untappd.Net/Authentication/AuthenticationHelper.cs b/src/Untappd.Net/Authentication/AuthenticationHelper.cs
index 7ce21e8..f7b59f3 100644
--- a/src/Untappd.Net/Authentication/AuthenticationHelper.cs
+++ b/src/Untappd.Net/Authentication/AuthenticationHelper.cs
@@ -18,6 +18,16 @@ namespace Untappd.Net.Authentication
         /// <returns></returns>
         public static string RedirectUserTo(IUnAuthenticadedUntappdCredentials credentials, string redirectUrl)
         {
+            if (credentials == null)
+            {
+                throw new ArgumentNullException("credentials");
+            }
+
+            if (string.IsNullOrWhiteSpace(redirectUrl))
+            {
+                throw new ArgumentNullException("redirectUrl");
+            }
+           
             return string.Format("{0}/?client_id={1}&response_type=code&redirect_url={2}", Constants.BaseRequestString,
                 credentials.ClientId, redirectUrl);
         }
@@ -31,6 +41,19 @@ namespace Untappd.Net.Authentication
         /// <returns></returns>
         public static string TokenUrl(IUnAuthenticadedUntappdCredentials credentials, string redirectUrl, string code)
         {
+            if (credentials == null)
+            {
+                throw new ArgumentNullException("credentials");
+            }
+
+            if (string.IsNullOrWhiteSpace(redirectUrl))
+            {
+                throw new ArgumentNullException("redirectUrl");
+            }
+            if (string.IsNullOrWhiteSpace(code))
+            {
+                throw new ArgumentNullException("code");
+            }
             return string.Format("{0}/?client_id={1}&client_secret={2}&response_type=code&redirect_url={3}&code={4}", 
                 Constants.OAuthTokenEndPoint, 
                 credentials.ClientId,