export injectAsync(tokens: any[], fn: Function) : FunctionWithParamTokens
export injectAsync(tokens: any[], fn: Function) : FunctionWithParamTokens
exported from angular2/testing defined in angular2/src/testing/test_injector.ts (line 223)
Allows injecting dependencies in beforeEach() and it(). The test must return
a promise which will resolve when all asynchronous activity is complete.
Example:
it('...', injectAsync([AClass], (object) => {
  return object.doSomething().then(() => {
    expect(...);
  });
})