Unable to implement HTTPMock from Managed package in Local Test Methods - Complete example with package

Question

A while ago SF began failing tests that make callouts without an HTTP mock. When they did that we were unable to deploy some trigger as a managed package made a callout whenever an Opportunity was inserted and thus the trigger test failed due to the callout. Unfortunately there was no way to tell the managed package to not make the callout.

I worked with the dev team to add a custom setting to allow us to bypass it.

This question prompted me to revisit the issue: Writing tests for Managed Package

What I did:

1. Created a managed package: https://login.salesforce.com/packaging/installPackage.apexp?p0=04t6A000000V12L

   I had to add a dummy class to it as it would not let me upload with only the test class so ignore those

   Mock Impl Class In package

   @isTest
   global class EchoHttpMock implements HttpCalloutMock {
   
       HttpResponse res;
   
       global EchoHttpMock(HttpResponse r) {
           res = r;
       }
   
       // This is the HttpCalloutMock interface method
       global HttpResponse respond(HttpRequest req) {
           system.debug(res.getBody());
           return res;
       }
   
       global static void setTestMockResponse(Integer statusCode, String status, String body) {
           HttpResponse mockResp = new HttpResponse();
   
           if (statusCode != null)
               mockResp.setStatusCode(statusCode);
   
           if (status != null)
               mockResp.setStatus(status);
   
           if (body != null)
               mockResp.setBody(body);
   
           test.setMock(
                   HttpCalloutMock.class,
                   New EchoHttpMock(mockResp)
           );
   
       }
   }
   

   Managed Callout Class

   global class managed_googleCallout{
   
   
     global static void doIt(){
   
         HTTPRequest req = New HTTPRequest();
         req.setEndpoint('http://www.google.com');
         req.setMethod('GET');
   
         system.debug(New Http().send(req).getBody());
   
   
     }
   }
   

   You can install this package in your org to validate this does not work.

2. I installed the package in my play org

3. I created a class that made a callout

   Callout Class

   public class local_googleCallout{
   
   
       public static void doIt(){
   
           HTTPRequest req = New HTTPRequest();
           req.setEndpoint('http://www.google.com');
           req.setMethod('GET');
   
           system.debug(New Http().send(req).getBody());
   
   
       }
   }
   

   Pretty simple (make sure you add the endpoint to remote site settings)

4. I made a local copy of the EchoHttpMock in the org using the name local_EchoHttpMock

5. I created a test class

   Local Test Class

   @isTest
   public class googleCalloutTest{
   
   public static testmethod void calloutTestManaged(){
       test.startTest();
   
       mockimpltest.EchoHttpMock.setTestMockResponse(200,'OK','The Body');
   
       local_googleCallout.doIt();
   
       test.stopTest();
   
   }
   
   public static testmethod void calloutTestLocal(){
       test.startTest();
   
       local_EchoHttpMock.setTestMockResponse(200,'OK','The Body');
   
       local_googleCallout.doIt();
   
       test.stopTest();
   
   }
   
   public static testmethod void calloutTestFromLocal_Managed(){
       test.startTest();
   
       mockimpltest.EchoHttpMock.setTestMockResponse(200,'OK','The Body');
   
       mockimpltest.managed_googleCallout.doIt();
   
       test.stopTest();
   
   }
   
   
   }
   

   I ran the test class and the local passes and the managed fails.

   

So, how is one supposed to implement a mock implementation from a managed package to support a callout during local test methods? If one wants to supply a testing framework to return particular responses to customers code / implementation it cannot be done.

Salesforce says this is supposed to work but I cannot get it to despite various attempts.

Update

Per Daniels comment, I added a class in the managed package that does a callout. When the mock implementation is implemented locally and the managed method is called the test does pass.

So it seems that only when local code is attempting to implement the callout and the mock implementation is when this occurs.

The initial observation when a trigger caused the callout

Update 3

As long as the callout originates from and the mock are implemented in the same namespace it works:

• Callout Local - > Mock Managed -> Fail
• Callout Managed -> Mock Local -> Fail
• Callout Local -> Mock Local -> Pass (obviously)
• Callout Managed -> Mock Managed -> Pass

API Version 39.0

Answer 1

I may have utterly misunderstood what you're doing here - apologies if I have - but I've regularly use a managed package (that we wrote) with a similar scenario.

Our package is one that we use within the company to simplify making callouts. So, instead of ever directly using

res = httpConnection.send(req);

We call that indirectly using package methods. (The package does things like simplifying error handling and tracking total callout time). I came across the same problem as you with testing and mocks.

In my case, there was no option to have the mock inside the managed package, because the host org is the only one who knows what the mock ought to look like.

It seems to me that Test.setMock works per namespace that it is invoked in, and is independent of where the actual mock is defined (as long as the mock is global).

So, in my managed package I have a method which only exists for inserting a mock into the right namespace:

global static void setMock(HttpCalloutMock theMock) {
    Test.setMock(HttpCalloutMock.class, theMock);
}

Then when I write a test in the host org, I use that instead of directly calling Test.setMock() in my test e.g.

    BrightTalkApiMock mock = new BrightTalkApiMock(settings, 200);

    Nebula_API.NebulaApi.setMock(mock);

Adding modification to Eric's code to clarify my point:

Here's Eric's test, modified to set the mock in the local namespace, but still use the mock defined in the package:

public static testmethod void calloutTestManaged(){
    test.startTest();

    HttpResponse mockResp = new HttpResponse();

    mockResp.setStatusCode(200);

    mockResp.setStatus('OK');

    mockResp.setBody('The Body');

    mockimpltest.EchoHttpMock theMock = new mockimpltest.EchoHttpMock(mockResp);
    Test.setMock(HttpCalloutMock.class, theMock);

    local_googleCallout.doIt();

    test.stopTest();

}

I think this is what you were trying to do, but the use of the static method to make the mock instance was confusingly tying together the definition and the setting of the mock.