FetchXml StateCode Specified Cast is not Valid

[karthikChakravartula]

We have a Custom Entity , we are using fetch Xml to retreive the Record.

When trying to Unit test the method it says Specified Cast is Not Valid when using retreive multiple.

We did generate Early bound Classes as Well.

Not sure what was missing.

Here is the Code below.

_context.EnableProxyTypes(Assembly.GetExecutingAssembly());

var pluginContext = _context.GetDefaultPluginContext();

`_context.Initialize(new List<Entity>() {
        _account,_envVariable
        });`

` var fetchXml = @"

                                            </fetch>";`

        `var rows = _context.GetOrganizationService().RetrieveMultiple(new FetchExpression(fetchXml));`

It is throwing specified error on retreive multiple.