Use assert_equals instead of snapshots

[Chemaclass]

What type of PR is this?

• [x] Refactor
• [ ] Feature
• [ ] Bug Fix
• [x] Optimization
• [ ] Documentation Update

Description

We added bashunit here https://github.com/CodelyTV/pr-size-labeler/pull/64 using snapshot testing as example. However, for these concrete tests it make more sense (as it is also simpler to read) to use a simple assert_equals

Snapshots make sense when the output to compare is something bigger/more complex than a number. When comparing a number, snapshot testing might be good for show-case example, but it is an overkilling feature for the long living of the project.

[Chemaclass]

Reminder: Can we merge this? :)