Add missing 'Assert' in GetFallbackLanguage_ReturnsFirstNonNullCultureFromSupportedCultureList

test/Microsoft.AspNet.Localization.Tests/AccessLanguageHeaderRequestCultureProviderTest.cs

@@ -42,6 +42,7 @@ namespace Microsoft.Framework.Localization.Tests
                 client.DefaultRequestHeaders.AcceptLanguage.ParseAdd("jp,ar-SA,en-US");
                 var count = client.DefaultRequestHeaders.AcceptLanguage.Count;
                 var response = await client.GetAsync(string.Empty);
+                Assert.Equal(3, count);
             }
         }