ErrorChecker.CheckForErrors C# (CSharp) Method

    public string CheckForErrors(PropertyData propertyData, bool isBeforeAfter)
    {
        var propertyDefinition = propertyData.PropertyDefinition;
        if (propertyDefinition.SetMethod.Name == "set_Item" && propertyDefinition.SetMethod.Parameters.Count == 2 && propertyDefinition.SetMethod.Parameters[1].Name == "value")
        {
            return "Property is an indexer.";
        }
        if (propertyDefinition.SetMethod.IsAbstract)
        {
            return "Property is abstract.";
        }
        if (propertyData.CheckForEquality && (propertyData.BackingFieldReference == null) && (propertyDefinition.GetMethod == null))
        {
            return "When using CheckForEquality the property set must contain code that sets the backing field or have a property Get. Either the property contains no field set or it contains multiple sets and the names cannot be mapped to a property.";
        }
        if (isBeforeAfter && (propertyDefinition.GetMethod == null))
        {
            return "When using a before/after invoker the property have a 'get'.";
        }

        return null;
    }

        public void WhenHttpResponseContainsBadUserErrorItIsDetectedAndAInvalidApiRequestIsThrown()
        {
            var response = new HttpResponseMessage(HttpStatusCode.BadRequest)
            {
                Content = new StringContent(BadUsernameOrPasswordResponseMessage)
            };

            ErrorChecker.CheckForErrors(response);
        }