Testing transformers is usually a low priority for me, since almost all of them have been good (knock on wood) in the TVs I have restored.
Sometimes a schematic will indicate the resistance you should expect to find on the various transformer windings. So, you can check that resistance if you like, being aware that any components connected in parallel may lower the resistance.
As with tube radios, the biggest single task in restoring an old TV is replacing capacitors, starting with the electrolytics in the power supply. The restoration section in my website has a number of TV articles that will give you a general idea what's involved in fixing these TVs.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html