Successful completion of theoretical knowledge examinations is required for the issue of licences and ratings and, with one exception, once the relevant licence or rating has been issued, the examinations become irrelevant. The exception is the IR where, if the rating has not been renewed within the preceding 7 years, the examinations must be passed again before it can be renewed. However, the latest amendment to Part-FCL removed this requirement for holders of a valid IR issued by an ICAO member state and so if you hold a valid CAAC IR you can renew your EASA IR with no requirement for exams or refresher training, irrespective of how long ago it expired (see FCL.625.IR(e)). The ATPL theoretical knowledge examinations are valid for the issue of an ATPL for the same 7 year period from the last renewal of the instrument rating. Consequently, by renewing the EASA IR, you automatically extend the validity of the ATPL exams for a further 7 years.
Note that the Regulation actually says "If the rating has not not been renewed within the preceding 7 years" whereas the UK CAA counts 7 years from the expiry date of the instrument rating, which is 8 years since it was last renewed. It should not be assumed that other member states will take the same liberal view.