"I have yet to test that."
Translation:Das muss ich noch prüfen.
I don't think the currently accepted translation fits at all.
"I have yet to test X" basically only says that I have not yet tested X. It does not explicitly mean that I will test X in the future; at most it implies some interested on my part in testing X.
"Das werde ich noch testen" does the opposite: It says nothing about whether I have tested X in the past, but does explicitly state my intention to test X in the future.