I don't get how asking for a sign from God equals testing God.
He tells us if we need wisdom and knowledge to ask Him. It doesn't mean we like the answer of course. We are to communicate with Him, there is always the chance of Satan getting into the mix. This is where discernment comes in . We shouldn't live paranoid lives afraid to ask God when we need clarity or understanding about something should we ? I think it is wise to make our requests to God in silent thought though. I was taught that God hears our thoughts, that while Satan can interject things into our minds, Satan can not hear our thoughts . But of course anyone could hear our vocalized requests. Also God is omnipresent and Satan is not, Satan has to send in his minions to get coverage, God hears every thought we have, good and bad. He also hears our healing thoughts for others.
Formal prayer not required, thoughts will do it and have done it, which is prayer in and of itself. In case no one has told you, Satan is a defeated doofus. He can only gain any kind of meaningful control over us if we let him. So don't let him. " Give no place to the devil" ( this means not to allow him a foot hold).
Ephesians 4:27 New King James Version (NKJV)
27 nor give a]">[
a]place to the devil.