# WARNING - Generated by {fusen} from dev/flat_kwb_simulate_inflow.Rmd: do not edit by hand # nolint: line_length_linter.


test_that("selectColumns works correctly", {
  df <- data.frame(a = 1:3, b = letters[1:3], c = c(TRUE, FALSE, TRUE))

  # Test with explicit columns
  expect_equal(selectColumns(df, columns = c("a", "b")), df[, c("a", "b")])

  # Test with pattern
  expect_equal(selectColumns(df, pattern = "a|b"), df[, c("a", "b")])

  # Test with drop = TRUE
  expect_equal(selectColumns(df, columns = "a", drop = TRUE), df$a)

  # Test with non-existing columns (do.stop = FALSE warns instead of stopping)
  expect_warning(res <- selectColumns(df, columns = c("a", "x"), do.stop = FALSE), "No such column")
  expect_equal(res, df[, "a"])

  # Test with NULL columns
  expect_equal(selectColumns(df, columns = NULL), df)

  # Test with NA columns
  expect_equal(selectColumns(df, columns = NA), df)

  # Test with empty columns
  expect_equal(selectColumns(df, columns = character(0)), df)

  # Test with non-data frame input
  expect_error(selectColumns(1:3, columns = "a"), ".*must be a data frame.*")

})