When I was in grade school we had a 25" color TV in a really nice wooden console. Whenever the set acted funny we'd get a shoe box, put all the tubes in it, drive down to the store and test all the tubes.

There were a bunch of sockets on the tester to accommodate the various tubes(I believe # of pins and space between pins differed). Then you'd set a dial to test the correct socket and get a pass/fail response. The new tubes were stored in the bottom of the tester unit.