options.plugins.title.font.size is ignored (3.0.0-beta.8 regression)

[StephanTLavavej]

Expected Behavior

options.plugins.title.font.size should control the title's size. This worked in 3.0.0-beta.7.

Current Behavior

options.plugins.title.font.size is ignored in 3.0.0-beta.8. I was unable to find any documentation about this being a known breaking change, nor was I able to find any samples with customized title sizes.

Possible Solution

I saw that #8227 changed src/plugins/plugin.title.js and seemed to involve the font, but as a JS novice, I don't see what caused the bug.

Steps to Reproduce

Live example with 3.0.0-beta.7 where options.plugins.title.font.size works:
https://codepen.io/StephanTLavavej/pen/yLaGzYa

Live example with 3.0.0-beta.8 where options.plugins.title.font.size is ignored:
https://codepen.io/StephanTLavavej/pen/mdraBeo

Context

I work on Microsoft's C++ Standard Library implementation, and started using Chart.js last year to create a Status Chart tracking our GitHub progress, at https://microsoft.github.io/STL/ . (Thank you! I was learning JavaScript from scratch, and Chart.js made things very easy.) We're currently using Chart.js v2.9.4, but I have a branch where I'm eagerly testing each beta of v3.0.0 so I can react to breaking changes and be ready for the final release. That's how I noticed this regression.

Environment

• Chart.js version: 3.0.0-beta.8
• Browser name and version: Chrome 87.0.4280.141
• Link to your project: https://github.com/StephanTLavavej/STL/tree/v3-pages is where I'm testing v3.0.0 betas

[StephanTLavavej]

Fix verified with 3.0.0-beta.9 - thanks @LeeLenaleee!
https://codepen.io/StephanTLavavej/pen/MWjZxgQ

It seems that there's missing test coverage for title fonts, but if there are no plans to add such tests, I'm happy for this issue to be closed. 😻

[etimberg]

Unfortunately it's pretty hard to test those kinds of things since each browser is slightly different, so generating a baseline rendering image isn't possible. We work around this by using custom text sprites. That being said, there are tests that should be updated to match so I will update those.