Sometimes when people point me on my mistakes in grammar or speech I say as a joke: "I was just checking you! :)" meaning that it was a trap, to see if people notice the mistake. However, today I was told that it is grammatically incorrect and I can't use the word "checking" in this context, and word "testing" should be used instead.
I am actually very perplexed, because I don't see a difference between "Just checking you" and "Just testing you". So, what is the correct word to choose?
Thanks in advance!