HTTP API to Google DistanceMatrix

public class DriveCode{
     @future (callout=true)  // future method needed to run callouts from Triggers
      public static void getDistance(){
        // gather account info
        Property__c [] a = [SELECT  Street_Address__c, 
                                  City__c, 
                                  State__c,
                                  Zip__c, 
                                  Service_Center__c,
                                  NeedDistance__c 
                                  FROM Property__c 
                                  WHERE Id ='a031Q00001wPRnYQAW'];
        if(a[1].NeedDistance__c == true){  
            // build callout
            String dstreet = ' ';
            String dcity = ' ';
            String dstate = ' ';
            String dzip = ' ';
            String saddress = ' ';
            if(a[1].Street_Address__c != null){dstreet = a[1].Street_Address__c;}
            if(a[1].City__c != null){dcity = a[1].City__c;}
            if(a[1].State__c != null){dstate = a[1].State__c;}
            if(a[1].Zip__c != null){dzip = a[1].Zip__c;}
            if(a[1].Service_Center__c != null){saddress = a[1].Service_Center__c;}
            String destaddress = EncodingUtil.urlEncode(dstreet + ' ' + dcity + ' ' + dstate + ' ' + dzip, 'UTF-8');
            String serveaddress = EncodingUtil.urlEncode(saddress, 'UTF-8');
            Http h = new Http();
            HttpRequest req = new HttpRequest();
            //req.setEndpoint('http://maps.googleapis.com/maps/api/distancematrix/json?origins=' + a[1].Origin_Zip__c + '&destinations=' + a[1].Destination_Zip__c + '&mode=driving&units=imperial&sensor=false');
            req.setEndpoint('http://maps.googleapis.com/maps/api/distancematrix/json?origins=' + destaddress +'&destinations=' + serveaddress + '&key=AIzaSyDgO1iTw2QWJMBbgn73ODqgryrZ6sLtWTw');
            //req.setEndpoint(EncodingUtil.urlEncode('http://maps.googleapis.com/maps/api/distancematrix/json?origins=' + a[1].Origin_Street__c + '+' + a[1].Origin_City__c + '+' + a[1].Origin_State__c + '+' + a[1].Origin_Zip__c + '&destinations=' + a[1].Destination_Street__c + '+' + a[1].Destination_City__c + '+' + a[1].Destination_State__c + '+' + a[1].Destination_Zip__c + '&mode=driving&units=imperial&sensor=false', 'UTF-8'));
            //req.setEndpoint(GEOCODING_URI_BASE + EncodingUtil.urlEncode(address, 'UTF-8'));
            req.setMethod('GET');
            req.setTimeout(60000);
            integer distance = null;
            string tdistance = null;
            //HttpResponse res = h.send(req);
            // callout
            HttpResponse res = h.send(req);
            System.debug(res.getBody());
            // parse coordinates from response
            JSONParser parser = JSON.createParser(res.getBody());
            while (parser.nextToken() != null) {
                if ((parser.getCurrentToken() == JSONToken.FIELD_NAME) &&
                    (parser.getText() == 'distance')){
                       parser.nextToken(); // object start
                       while (parser.nextToken() != JSONToken.END_OBJECT){
                           String txt = parser.getText();
                           parser.nextToken();
                           if (txt == 'text')
                               tdistance = parser.getText();
                           else if (txt == 'value')
                               distance = parser.getIntegerValue();
                       }
                }
            }
            // update coordinates if we get back
            if (distance != null){
                a[1].Distance_Miles__c = distance;
                //a[1].tdistance__c = tdistance;
                a[1].NeedDistance__c = False;
                //a[1].Description1__c = req.getEndpoint();
                //a[1].Description2__c = res.getBody();
                //String originaddress = a[1].Origin_Street__c != null ? a[1].Origin_Street__c + ' ' : '' +
                //a[1].Origin_City__c != null ? a[1].Origin_City__c + ' ' : '' +
                //a[1].Origin_State__c != null ? a[1].Origin_State__c + ' ' : '' +
                //a[1].Origin_Zip__c != null ? a[1].Origin_Zip__c : '';
                //String originaddress = EncodingUtil.urlEncode(a[1].Origin_Street__c + ' ' + a[1].Origin_City__c + ' ' + a[1].Origin_State__c + ' ' + a[1].Origin_Zip__c, 'UTF-8');
                a[1].LinkToDirections__c = 'http://maps.googleapis.com/maps/api/distancematrix/json?origins=' + destaddress +'&destinations=' + serveaddress + '&key=AIzaSyDgO1iTw2QWJMBbgn73ODqgryrZ6sLtWTw';
                //a[1].Description1__c = EncodingUtil.urlEncode(originaddress, 'UTF-8') + '---' + originaddress;
                update a;
            }
        } 
          Else {
              a[1].LinkToDirections__c = 'test';
              a[1].NeedDistance__c = True;
              update a;
          }
      }
}

@isTest
private class DrivefutureTest {
    @isTest static void test1() {
            // startTest/stopTest block to run future method synchronously
            Test.startTest();        
            DriveCode.getDistance();
            Test.stopTest();
        }
}