x <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,      1 ,  100 ,
  "chr1" ,    200 ,  500
)
y <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,      1 ,  100 ,
  "chr1" ,    200 ,  500
) |>
  group_by(chrom)

test_that("NULL is return when there are no shared groups, shared_groups()", {
  res <- shared_groups(x, y)
  expect_null(res)
})

test_that("only shared groups are return, shared_groups()", {
  x <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,      1 ,  100 ,
    "chr1" ,    200 ,  500
  ) |>
    group_by(chrom, start, end)

  res <- shared_groups(x, y)
  expect_true(length(res) == 1 && res == "chrom")
})


x <- tibble::tribble(
  ~end , ~chrom , ~start , ~value ,
    75 , "chr1" ,    125 ,     10
)

y <- tibble::tribble(
  ~chrom , ~start , ~end , ~scores ,
  "chr1" ,     50 ,  100 , 1.2     ,
  "chr1" ,    100 ,  150 , 2.4
)

test_that("x columns are reordered based on y, reorder_names()", {
  res <- reorder_names(x, y)

  pred <- intersect(colnames(y), colnames(res))
  n <- length(pred)

  expect_true(all(colnames(res[1:n]) == pred[1:n]))
})