@RestResource (urlMapping='/DeviceObjserviceendpoint/*')
global class DeviceObj_Rest_Service {
  
    @HttpGet
    global static void doGetDevice() {
        String result = '';
        try{
        Map<string, string> paramsMap = RestContext.request.params;
      if(paramsMap!=null){
        String serialNo = paramsMap.get('serialNo');
        String lastName = paramsMap.get('lastName');
        String dateOfBirth = paramsMap.get('dateOfBirth');  
                 Date dob = date.parse(dateOfBirth);
            
       
        //Date dob = date.parse(dateOfBirth);
        List<Device__C> Devs = [Select Id, Name,Dob__c,Patient_Last_Name__c from Device__C 
                                where Name = :SerialNo and  
                                Patient_Last_Name__c =:lastName and 
                                DOB__c = :dob
                                LIMIT 1];

         if( Devs.size() > 0 ) {
             Device__C Dev = Devs[0];
            Map<String,String> resultMap = new Map<String,String> {
                'Message'  => 'Device found Sucessfully',
                'DeviceId' => Dev.Id,
                'SerialNo' => Dev.Name,
                'DateOfBirth' => string.valueof(Dev.Dob__c),
                 'lastname' =>Dev.Patient_Last_Name__c
            };
           
          result = JSON.serialize( resultMap );
       
         }
        else {
            result = 'Device with SerialNo :' + SerialNo + ' not found!';
        }
        }
        }catch(Exception ex){
            result= ex.getMessage();
        }
        RestContext.response.addHeader('Content-Type','application/json');
        RestContext.response.responseBody = Blob.valueOf(result);
    
         }
    
}

@isTest
private class DeviceObj_Rest_Service_Test {
    
    static testMethod void testDoGetDevice() {
         Id stExam = Schema.SObjectType.Account.getRecordTypeInfosByName().get('Patient').getRecordTypeId();
         system.debug(stExam);
         
         Account acc = new Account(FirstName = 'Test', LastName = 'Test22', PersonEmail = 'testaccount@test.com', RecordTypeId = stExam);
         insert acc;  
            
       
        // create a new Device record
        Device__c device = new Device__c(Name = '1234567890', type__c='Test',Patient__c= acc.id);
        insert device;
        
        // test a valid GET request
        RestRequest request = new RestRequest();
        request.requestURI = '/services/apexrest/DeviceObjserviceendpoint';
        request.addParameter('serialNo', device.Name);
        request.addParameter('lastName', device.Patient_Last_Name__c);
        request.addParameter('dateOfBirth', String.valueOf(device.DOB__c));
        RestContext.request = request;
        
        Test.startTest();
        DeviceObj_Rest_Service.doGetDevice();
        Test.stopTest();
        
        RestResponse response = RestContext.response;
      
    }
    
}