In any case, there are also districts that are continuing to cite MGL that there is no right to not take the test (whatever it is called), and it appears that some are preparing to argue this with parents, rather than the relative merits of the test(s), as they have been directed to do by the state (edit: possibly even Worcester, though I haven't seen that yet).
The best place to come back to on this is the Commissioner's memo to districts of October 15. Again, that says the following:
If the building principal has provided this information to the parent and student and the student still refuses to participate in the state assessments, the principal should see to it that the student is engaged in an alternate educational activity and is not distracting other students during the testing period. In some cases it may be appropriate for the student to be removed from the testing room. The test administrator's manual will include instructions for reporting a student's refusal to participate.I'd also recommend that any parent planning this discover just what the district plans with their child: will the district require that the student be put in front of the test and say 'no' him or herself in order to count as a refusal? And then what will the school do?
And while you can certainly cite me as a source, I'd recommend just citing the Commissioner directly.