public void GetCustomPropertyValueThrowsExceptionIfMultiplePropertiesFound()
{
const string propertyName = "SomeProp";
claimsIdentity.AddClaim(new Claim(ClaimTypePrefix.CustomProperty + propertyName, "Foo"));
claimsIdentity.AddClaim(new Claim(ClaimTypePrefix.CustomProperty + propertyName, "Bar"));
sut.GetCustomPropertyValue(propertyName);
}