test_that("missing path yields header error object", {
  path <- tempfile(fileext = ".vcf")
  x <- parse_vcf_header(path)

  expect_s3_class(x, "vcf_hdr")
  expect_true(length(x$errors) >= 1)
  expect_match(x$errors[[1]], "Empty or missing header")
})

test_that("validator warns when no samples are detected", {
  tf <- tempfile(fileext = ".vcf")
  writeLines(
    c(
      "##fileformat=VCFv4.2",
      "##INFO=<ID=DP,Number=1,Type=Integer,Description=\"Total Depth\">",
      "#CHROM\tPOS\tID\tREF\tALT\tQUAL\tFILTER\tINFO"
    ),
    tf
  )

  x <- parse_vcf_header(tf)

  expect_true("No samples detected" %in% x$warnings)
  expect_equal(length(x$errors), 0)
})

test_that("validator reports duplicate INFO IDs", {
  tf <- tempfile(fileext = ".vcf")
  writeLines(
    c(
      "##fileformat=VCFv4.2",
      "##INFO=<ID=DP,Number=1,Type=Integer,Description=\"Depth one\">",
      "##INFO=<ID=DP,Number=1,Type=Integer,Description=\"Depth two\">",
      "#CHROM\tPOS\tID\tREF\tALT\tQUAL\tFILTER\tINFO"
    ),
    tf
  )

  x <- parse_vcf_header(tf)

  expect_true(any(grepl("Duplicate INFO IDs", x$warnings)))
})