If DPS did not already have an open file in this case, the worst thing you could do is to cause a file to be opened. I know that a file was opened by the other side. However, if you agreed to be tested (and the test is negative), the file may very well be closed as unsubstantiated. If you refuse to comply, the file will not be closed and you may be sorely disappointed with the resulting consequences.
The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change.
The problem with the question is that it's your opinion that CPS has requested a drug test for no reason. There is no way for anyone but you to know why exactly they are requesting a drug test. That being said though, think about the silent implications of your refusal to cooperate. Usually I suggest for people to take the drug test and clear their names rather than drag out the process. It is of course, based on the situation itself, and you may have a valid reason to refuse to take a drug test. Your best bet is to consult with an attorney and lay out the entire situation for him or her.
My advice is to cooperate with CPS. If you know your test is going to come up positive - you should talk to an attorney in your area who does CPS cases before you take the test. Otherwise - non-cooperation with CPS can be futile. You have a right to refuse and they have a right to further pursue a case based on the hearsay evidence they have received and your refusal to cooperate. CPS cases in California are called Juvenile Dependency cases. Make sure the attorney you speak with is a Juvenile Dependency attorney.
Sign up to receive a 5-part series of useful information and advice about child custody law.