I would think that's a pretty reasonable test. Generally they work or they don't. Aside from weak batteries ( which I bet you have changed ) there is not much more to suspect.
Only other thin I can think of is poor range caused by a dirty lens on the remote, or the TV. Some remotes have the LED exposed, if so, it's not that.
If anyone in the house smokes, it can coat the window ( inside and out ) on the front of the remote with a sticky film that attracts dust and limits the range of the remote. Same applies for the TV. The remotes window is easy to clean, the TV's, well not so much.
As an aside, some TV's have an maddening narrow "viewing cone" for the remote control, and anything that weakens the remote signal magnifies the problem greatly. My JVC is like that, once the batteries get slightly weak, it's like laser tag with the remote.