Fix class error@main

[BFalquet]

bug spotted by @barnett11 in lbt05

The error I see is below,
Error in `arrange()`:
! Can't transform a data frame with `NA` or `""` names.
Run `rlang::last_trace()` to see where the error occurred.

I believe I've located issue at this section specifically within the main function,
map <- expand.grid(PARAM = levels(adam_db$adlb$PARAM), ABN_DIR = c("Low", 
        "High"), stringsAsFactors = FALSE) %>% arrange(.data$PARAM, 
        desc(.data$ABN_DIR))

This is due to the fact the PARAM is expected to be a factor by the level function. Automatic conversion to factor can cause unexpected behavior and is, in general, avoided.

Defensive approach is to modify the assertion to force PARAM to be a factor.

• adapt assertion
• add tests

thank you for the review

[github-actions]

Unit Tests Summary

  1 files   58 suites   3m 23s ⏱️
293 tests 292 ✅ 1 💤 0 ❌
687 runs  678 ✅ 9 💤 0 ❌

Results for commit b80ab97.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Performance Difference

Additional test case details

Test Suite	$Status$	Time on main	$±Time$	Test Case
lbt05	👶		$+0.71$	lbt05_works_with_missing_levels

Results for commit 1a723c1

♻️ This comment has been updated with latest results.

[shajoezhu]

lgtm! thanks to Tim's explaination