class...

    public class ExceptionCreateExceptionRecord{
    public static void insertException(Map<string, string> param)
    {    
    	Exception__c newExcept              =   new Exception__c();
            newExcept.ExceptionTypeCode__c      =   param.get('ExceptionTypeCode__c');
            newExcept.RecordType.DeveloperName  =   'New Exception'; 
		
		
test class

    @isTest(SeeAllData=true)
    public class TestExceptionCreateExceptionRecord {
       static testmethod void Exception(){
        map<String ,String> parm=new map<String,String>();
            parm.put('ExceptionTypeCode__c', 'open');                
            parm.put('entry2','Second entry'); 
       ExceptionCreateExceptionRecord excep=new ExceptionCreateExceptionRecord();   
        ExceptionCreateExceptionRecord.insertException(Parm);
		
		
stacktrace

> Class.ExceptionCreateExceptionRecord.insertException: line 7, column
> 1( newExcept.RecordType.DeveloperName  =   'New Exception'; )
> Class.TestExceptionCreateExceptionRecord.Exception: line 8, column 1(
> ExceptionCreateExceptionRecord.insertException(Parm);)