Increase test coverage for priority files with lowest coverage

[Copilot]

Added 320 lines of tests targeting the 6 files with lowest coverage (51.52% - 86.84%), focusing on untested code paths, edge cases, and error handling.

Coverage improvements by file

• R/sort.R (51.52%): Deprecated parameter warnings, empty dataframes, partial variable sets
• R/supp.R (70.05%): Invalid input validation, column conflict detection, NA IDVAR handling
• R/utils.R (75.00%): Invalid file paths, make_lone_dataset edge cases
• R/labels.R (77.78%): Empty ellipsis, unlabeled data, variable mismatches
• R/checks.R (85.44%): strict=FALSE behavior, numeric vs character NA handling
• R/build.R (86.84%): Unknown data types, predecessor_only=TRUE, empty variable drops

Test patterns

All deprecated dataset_name parameters now have warning tests:

test_that("order_cols with deprecated dataset_name parameter", {
  expect_warning(
    order_cols(data, metacore, dataset_name = "ADSL"),
    "was deprecated in metatools 0.2.0"
  )
})

Edge cases for boundary conditions:

test_that("order_cols with empty data frame", {
  empty_data <- data[0, ]
  result <- order_cols(empty_data, spec)
  expect_equal(nrow(result), 0)
})

Error path validation:

test_that("combine_supp handles invalid inputs correctly", {
  expect_error(
    combine_supp("not a dataframe", safetyData::sdtm_suppae),
    "You must supply a domain and supplemental dataset"
  )
})

Original prompt

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This section details on the original issue you should resolve

<issue_title>Increase Test Coverage</issue_title>
<issue_description>We should improve test coverage across the package, with priority on the files with the lowest coverage. This will help catch bugs earlier and make the codebase more maintainable.
Files needing attention

R/sort.R (51.52%) - Highest priority
R/supp.R (70.05%)
R/utils.R (75.00%)
R/labels.R (77.78%)
R/checks.R (85.44%)
R/build.R (86.84%)</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Increase Test Coverage #117

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[jeffreyad]

Closing this one