Parameters not coerced when visiting a Lookbook preview in a Rails system test

[camertron]

Describe the bug

Hey there 👋 It's me again! Just popping in to describe some unexpected behavior around param coercion. My pair and I noticed today that visiting a Lookbook preview in a system test does not result in properly coerced parameters. We're visiting like this:

visit "/page?my_param=foo"

In the preview code, the #preview_name method has an @param annotation for the my_param parameter that indicates it should be coerced to a symbol. Unfortunately, the coercion does not occur:

# @param [Symbol] select [foo, bar]
def preview_name(my_param: :foo)
  # my_param is a string here
  ...
end

To Reproduce

Steps to reproduce the behavior:

1. Create a preview as described above.
2. Render that preview in a Rails system test.
3. Observe that parameters are not coerced.

Expected behavior

I expect the my_param parameter to be of type Symbol instead of String.

Version numbers

Please complete the following information:

• Lookbook: 2.3.2
• ViewComponent: 3.13.0
• Rails: 7.1.3
• Ruby: 3.3.3

[allmarkedup]

Hey @camertron 👋

Thanks for reporting this. To be honest I would have expected that this should 'just work' but I must admit I don't know a whole lot about how Rails system tests work under the hood...

I haven't had a lot of time to spend on Lookbook recently but as soon as I get a chance I'll dig into this, would be interesting to figure out what is going on here.