fix: ensure stubService returns reference to the service

Author: alexlafroscia

README.md

@@ -25,12 +25,10 @@ import td from "testdouble";
 import { stubService } from "ember-cli-testdouble/test-support";
 
 test("verifying a method invocation", function(assert) {
-  assert.expect(0); // Won't actually use `assert` in this test
+  // `stubService` returns a reference to the servive
+  let someStubbedService = stubService("some-service");
 
-  stubService("some-service");
-
-  let someService = this.owner.lookup("service:some-service");
-  someService.method();
+  // Do something that would call `method()` on the service
 
   td.verify(someService.method()); // Passes!
 });

addon-test-support/stub-service.js

@@ -35,7 +35,7 @@ export default function stubService() {
     let [name] = arguments;
     let { owner } = getContext();
 
-    replace(owner, name);
+    return replace(owner, name);
   } else {
     throw new Error("Unexpected number of arguments");
   }

tests/unit/test-support/stub-service-test.js

@@ -18,14 +18,19 @@ module("Test Helpers | stub-service", function(hooks) {
 
   module("invoking without `hooks`", function(hooks) {
     hooks.beforeEach(function() {
-      stubService("to-stub");
+      this.service = stubService("to-stub");
     });
 
     test("it can replace a service", function(assert) {
       let service = this.owner.lookup("service:to-stub");
       service.method();
 
       assert.verify(service.method());
+      assert.equal(
+        service,
+        this.service,
+        "Returns a references to the stubbed service"
+      );
     });
   });
 });