A testimony is having a conviction of the fabulous view provided by a nearby mountain to. Faith is to believe the view is great and worthwhile and making the effort to climb the mountain.
I'd rather have testimony of one thing and hundred percent faith than testimony of hundreds of things and lack faith to pursue any of them for myself.
If we accept payment in testimony when only the currency of faith is legal tender, we will short change ourselves. Instead of worshipping the true God, we send with the low quality copy and become of idolaters.
It's notable that Jesus often spoke of belief and faith in him but never about having a testimony.
Let me remind us about this: A parable: The pit, the village and the mountain