Injector silently ignoring definitions

[sellmair]

One Issue I found when creating PR #4 is that I had to add an Injector.clearDependencies() in front of the Singleton test to get it working like:

  test('Register singleton / Get singleton - Test', () {
    injector.clearDependencies();
    ...

The reason is, that trying to register a singleton dependency will silently be ignored if the dependency is already declared as factory!

Check out this snippet from the registerSingleton:

  void registerSingleton<T>(Factory<T> factory) {
    int key = T.hashCode;

    if (T == dynamic) {
      throw Exception(
          "No type specified !\nCan not register dependencies for type \"$T\"");
    }

   // TODO: Should also check the factory map!

    if (_singletonMap.containsKey(key)) {
      throw Exception("type \"$T\" already defined !");
    }

    _singletonFactoryMap[key] = factory;
  }

The factory definition will be used because it is preferred in getDependency

  T getDependency<T>() {
   // ...
    if (_factoryMap.containsKey(type)) {
     // get it from the factory
    } else {
      // get it from the singletons (factory or instance)
    }