This font contains two glyphs — + (U+2B) and - (U+2D) — each rendered as a
simple filled black rectangle. The simplicity makes screenshot tests insensitive
to font-rendering/antialiasing differences across platforms.
Regenerating
Install dependencies:
pip3 install fonttools brotli
Run generate_font.py to regenerate iconfont.woff2:
python3 tests/assets/webfont/generate_font.py