Documentation: Guidance for creating toy datasets in testthat

[bms63]

Background

So...this might seem a bit trivial/pedantic/crazy-town, but having the toy datasets readable for testing is really nice! When you run styler on it it can squish everything together making it unreadable.

However, with some finessing we can stop styler from doing the squish and keep things readable. There is some nuances to it

• Character variables should be left-aligned
• numeric variables should be right-aligned.
• The spacing counts, check out BASETYPE in image

See this PR for some more discussion:
pharmaverse/admiral#2560

Definition of Done:

• Enhance testing documentation to draw attention to this readability enhancement
• Create a few toy examples showcasing this
• Stress in documentation that this is nice to have but not required

[bms63]

@bundfussr sorry threw this together, but I think we should make some updates to testing that we can encourage users to take a look at to help with readability of the tests.

[bundfussr]

Once the guidance is available we could add a link to it in the pull request template. Then it is easier to find. The issue comes up frequently.