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.

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);

  }

}