How can you test whether a ceramic T1A 250 VAC fuse is good or not? I'm not an electrician but I do have a Gardner Bender Digital Multimeter Model GDT-3190.
It depends on what you mean by "good". If you want to see if the fuse has blown, then you can just use the "continuity test" setting, or check resistance. The fuse should have less than an ohm of resistance across its terminals.
If by "good", you want to check the fuse to see if it's really going to blow at its rated current, I'm not aware of any non-destructive test for that.
Remove the fuse and either
Set your multimeter to "continuity" and check that it beeps when connected to the fuse.
Set your multimeter to Ohms (lowest range if manual ranging) and check the resistance is close to 0.0 ohms.
If you want to check a sample fuse from a batch to ensure it will blow when subjected to an overload, you'll have to set up a more elaborate test rig.