Is there a purity test for crack cocaine?

I do not know of and have not heard of a purity test for crack cocaine in all my years experience. If you are trying to sell crack cocaine you should cook it up yourself, never buy it already cooked (Hard) from somebody or another dealer. It is not that hard to cook up (simple math and science) , and you will know it is pure because you will test the raw cocaine needed to make it( before cooking it), ( you can buy the test of the internet). If you are a crack cocaine smoker you should try to only buy it from a reputable seller or a seller you trust and had credibility. Also never behave like a junkie or act desperate because a dealer might see you as an easy target, and try to give you some bad or some "dummy crack". Or maybe perhaps investing in being able to support your hobby by producing it yourself in a small manner.