No, you're right, you're not.
You've just misunderstood what that website is saying.
That's quoting paragraph 148 of the opinion of the Advocate General in a paragraph entitled. 'The judgment departs from the Opinion of the Advocate General in three respects.' That is here:
http://curia.europa.eu/juris/docume...en&mode=req&dir=&occ=first&part=1&cid=1295347
A good faith requirement is being mentioned specifically as one of the three points that the judgement differs from the Opinion that the Advocate General gave, as your own quote actually says: ' The judgment does not confirm any such further substantive conditions.'
And I quoted you the judgement in full above. It very clearly states '[A member state can] revoke that notification unilaterally, in an unequivocal and unconditional manner, by a notice addressed to the European Council in writing'. A good faith requirement would be a condition.
Here is the judgement, btw:
http://curia.europa.eu/juris/docume...x=0&doclang=EN&mode=req&dir=&occ=first&part=1