[missing_small_caps_glyphs] is Just Wrong

[simoncozens]

Fonts without small caps pass this check. Indeed, every font in the GF library passes this check.

Here's why:

fontbakery/Lib/fontbakery/checks/missing_small_caps_glyphs.py

Lines 30 to 36 in fb1c3de

	smcp_glyphs = set()
	for value in subtable.mapping.values():
	if isinstance(value, list):
	for v in value:
	smcp_glyphs.add(v)
	else:
	smcp_glyphs.add(value)

For each lookup which corresponds to an smcp or c2sc feature, we gather a list of all the substituted glyphs (stuff on the right hand side of a sub ... by statement, e.g. a.sc).

fontbakery/Lib/fontbakery/checks/missing_small_caps_glyphs.py

Line 37 in fb1c3de

missing = smcp_glyphs - set(ttFont.getGlyphNames())

And then from that set of substituted glyphs, we remove every glyph in the font.

The result is that, unsurprisingly, no glyphs are missing.

[felipesanches]

PR #4721