add some more precision tests

[keithamus]

just some tests

[primer-css]

:wave: Hello and thanks for pinging us! This issue or PR has been added to our inbox and a Design Infrastructure first responder will review it soon.

• :art: If this is a PR that includes a visual change, please make sure to add screenshots in the description or deploy this code to a lab machine with instructions for how to test.
• :fast_forward: If this is a PR that includes changes to an interaction, please include a video recording in the description.
• :warning: If this is urgent, please visit us in #primer on Slack and tag the first responders listed in the channel topic.