Testing the Spirits

The other day I was approached by a member of the cult. They said “We are CHRISTians” even though they deny that Jesus is the Christ, the one and only Son of God.
I John 4:2 “Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge that Jesus is not from God.”
A cult will try to pass themselves off as Christians. But the way you test them is to discuss Jesus Christ. Is Jesus from eternity? Is He eternal? If He was created or if He came after God, then that is heresy, a cult.