I am a new bee to Angular JS and was trying to make something out of it in a proper TDD way, but while testing i am getting this error:
Injector alrea
You're using the inject function wrong. As the documentation states, the inject function already instantiates a new instance of $injector. My guess is that by passing $injector as a argument to the inject function you are asking it to instantiate the $injector service twice.
Just use inject to pass in the service you want to check. Underneath the covers, inject will use the $injector service it instantiates to grab services.
You can fix this problem by changing the second beforeEach statement to:
beforeEach(inject(function(_authorService_) {
authorService = _authorService_;
}));
One other thing to note. The argument authorService passed to the inject function has been wrapped with '_' so it's name does not hide the variable created within the describe function. Thats also documented in the inject documentation.