Writing Unit Tests for v24 Apex REST Services

With the Spring '12 release, salesforce.com made some great enhancements to Apex REST services (v24):

Apex REST automatically provides the REST request and response in your Apex REST methods via a static RestContext object. You no longer need to declare a RestRequest or RestResponse parameter in your method.
User-defined types are now allowed as Apex REST parameter types.
Apex REST methods are now supported in managed and unmanaged packages.

The order of elements in the JSON or XML response data no longer has to match the Apex REST method parameter order.</ul>

My favorite is the user-defined types. My REST services can now pass back a wrapper class with error messages along with the actual data. Here's what my new REST service looks like:

@RestResource(urlMapping='/v.9/member/*/results/*') 
global with sharing class MemberRestSvc {
 
 @HttpGet 
 global static ReturnClass doGet() {
 
  String[] uriKeys = RestContext.request.requestURI.split('/');
  // get the member name from the uri
  String memberName = uriKeys.get(uriKeys.size()-3);

  // do awesome programming stuff here & catch any exceptions
  try {
 
 List<Contact> contacts = [Select Id From Contact where member_name__c = :memberName];
 return new ReturnClass('true', 'Query executed successfully.', contacts);
  
  } catch (Exception e) {
 return new ReturnClass('false', e.getMessage(), null);
  }

 }

 global class ReturnClass {
  
  global String success;
  global String message;
  global List<Contact> records;
  
  global ReturnClass(String success, String message, List<Contact> records) {
 this.success = success;
 this.message = message;
 this.records = records;
  }
  
 }
  
}

So now that I have my service written and running like a champ, I just need to write my unit tests. If I was writing the unit test with the previous API (v23), I would write my unit test like:

@isTest
private class Test_MemberRestSvc {
 
 static {
  // setup test data 
 }
 
 static testMethod void testDoGet() {
  
  RestRequest req = new RestRequest(); 
  RestResponse res = new RestResponse();

  // pass the req and resp objects to the method 
  req.requestURI = 'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today'; 
  req.httpMethod = 'GET';

  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet(req,res);
  
  System.assertEquals('true', results.success);
  System.assertEquals(10, results.records.size());
  System.assertEquals('Query executed successfully.', results.message);
 
 }
 
}

Since v24 now includes a static RestContext object, testing is a little different as you no longer need to pass a Request and Response object to the method. I searched the Apex docs but there was no mention of writing unit tests. Pat Patterson has a good blog post for Apex REST but no mention of unit testing either.

So I tried a few routes for an hour or so to no avail. I finally IM'd Pat and begged for help. I posted the question on the Force.com Discussion Boards and Pat went to work. However, before Pat could finish his investigation and provide a solution, Kartik beat him to it (thanks!!).

So here's what the unit test looks like for a v24 Apex REST service. Notice that you pass a request and response object to the RestContext but that's it. Doesn't seem very intuitive?

@isTest
private class Test_MemberRestSvc {
 
 static {
  // setup test data 
 }
 
 static testMethod void testDoGet() {
  
  RestRequest req = new RestRequest(); 
  RestResponse res = new RestResponse();
 
  req.requestURI = 'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today'; 
  req.httpMethod = 'GET';
  RestContext.request = req;
  RestContext.response = res;

  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet();
  
  System.assertEquals('true', results.success);
  System.assertEquals(10, results.records.size());
  System.assertEquals('Query executed successfully.', results.message);
 
 }
 
}