Be forewarned: A lot of these kits only test for the presence of, not quality/purity of, MDMA and other forms of E. That being said, someone would definitely pipe up and say "this killed my friend" if something were to go wrong.
A test I learned in jail from petty computer trespassing charges when I was a kid is to light a small amount of powder on fire sitting on foil, if the residue is cherry red it's mainly mdma and not piperazines. Once again prison is criminal university.
If regeant testing a pill break it in half and test the inside too since often the outside is coated in mdma and the inside is shitty pipes
Testing kits and services are also available so you could review the quality without even taking the drug.