No, it's not. It's quite simple. There are only a few types of fonts available - TrueType, PostScript, bitmap, maybe others? At any rate, you test a couple of

No, it's not. It's quite simple. There are only a few types of fonts available - TrueType, PostScript, bitmap, maybe others? At any rate, you test a couple of examples of each type. Paint is a bitmap graphic generator, right? Apply letters in a test font to a bitmap, and compare the resulting bitmap to an expected value. We don't need to test every possible font there is. We only need to test enough fonts to cover the likely failure cases and known bugs. Speaking of bugs, suppose we find a bug with a specific font, or a specific size of font, or something like that. We write a test that exercises the bug, then fix the bug. Because it's a one-off test, it's not a tremendous burden to write. Moreover, that bug will never come back undetected again.