Add timepicker helper with added expectation to reduce flakiness

[mkllnk]

What? Why?

• Closes [Flaky] ./spec/system/admin/order_cycles/edit_spec.rb:65 #12786

What should we test?

• Specs only.
• 100/100 passes locally.
• 140/140 passed on CI.

Release notes

Changelog Category (reviewers may add a label for the release notes):

• User facing changes
• API changes (V0, V1, DFC or Webhook)
• Technical changes only
• Feature toggled

The title of the pull request will be included in the release notes.

Dependencies

Documentation updates

[mkllnk]

This may still fail if CI is having a bad day and is very slow but then we can just increase the sleep time. It's only a fraction of a second and not noticeable by a human at the moment.

[dacook]

It'd be great if we could find an expectation for when Flatpickr has updated. But in the meantime this is a very reasonable fix!

[dacook]

Thank for fixing this, I hope this is the last we see of it!
I'm curious, how did you run the test 140 times on CI? Did you write a temporary custom script on your branch?

[mkllnk]

c37bdeb#diff-5c3fa597431eda03ac3339ae6bf7f05e1a50d6fc7333679ec38e21b337cb6721R87

I changed the CI script to run only the one test case. The existing matrix for Knapsack ran that 14 times. Example:

• https://github.com/openfoodfoundation/openfoodnetwork/actions/runs/12421759049/job/34682119972

I then created an empty commit locally and pushed to Github. That triggered 14 runs in my repo on the branch and 14 in the OFN repo on the pull request. That's 28 in total. I repeated that a few times and I easily got to 100 hundred.

In the end, I removed the commit above, I could have reverted it for transparency.