from the quest issue: emberjs/ember.js#16373

specifically, this partially covers:

• Fix lib/models/project.js's isModuleUnification method to not only rely on presence of top level src as "the project is module unification format". Specifically, an addon may be in module unification format, but have its dummy app be in classic format.
• Ember CLI uses the presence of src/ to configure the return value of isModuleUnification(). This works well for apps and addons. The detection fails for a classic dummy app in a module unification addon, however. Although a dummy app may be in tests/dummy/app/ with no tests/dummy/src/ directory, the addon's root level src/ confuses our logic and the dummy app is incorrectly treated as a module unification app.

proposed scheme for multiple dummy apps:

• <root>/
  • tests/
    • dummy/
      • {app-name1}
        • a classic app
      • {app-name2}
        • a mu app