x <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,     10 ,   20 ,
  "chr1" ,     30 ,   40
)

y <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,     15 ,   20
)

test_that("jaccard coeff is calculated correctly", {
  res <- bed_jaccard(x, y)
  expect_equal(res$jaccard, 0.25)
})

test_that("jaccard coeff is calc'd for large data sets", {
  genome <- read_genome(valr_example("hg19.chrom.sizes.gz"))

  x <- bed_random(genome, n = 1e5, seed = 10000)
  y <- bed_random(genome, n = 1e5, seed = 20000)

  res <- bed_jaccard(x, y)
  expect_equal(round(res$jaccard, 3), 0.016)
})

test_that("jaccard with grouped inputs are calculated", {
  genome <- read_genome(valr_example("hg19.chrom.sizes.gz"))

  x <- bed_random(genome, n = 1e5, seed = 10000)
  y <- bed_random(genome, n = 1e5, seed = 20000)

  res <- bed_jaccard(
    group_by(x, chrom),
    group_by(y, chrom)
  )

  expect_equal(nrow(res), 24)
  expect_true("chrom" %in% names(res))
})

# from https://github.com/arq5x/bedtools2/blob/master/test/jaccard/test-jaccard.sh
test_that("Test symmetry", {
  res <- bed_jaccard(x, y)
  res2 <- bed_jaccard(y, x)
  expect_equal(res$jaccard, res2$jaccard)
})

test_that("Test jaccard with mixed strand files", {
  a <- tibble::tribble(
    ~chrom , ~start , ~end , ~name , ~score , ~strand ,
    "chr1" , 10L    , 50L  , "a1f" ,  2L    , "+"     ,
    "chr1" , 20L    , 60L  , "b1r" ,  4L    , "-"     ,
    "chr1" , 25L    , 70L  , "c1q" ,  8L    , "."     ,
    "chr1" , 30L    , 75L  , "d1q" , 16L    , "."     ,
    "chr1" , 40L    , 80L  , "e1f" , 32L    , "+"     ,
    "chr1" , 45L    , 90L  , "f1r" , 64L    , "-"     ,
    "chr2" , 10L    , 50L  , "a2q" ,  2L    , "."     ,
    "chr2" , 20L    , 40L  , "b2f" ,  4L    , "+"     ,
    "chr2" , 25L    , 50L  , "c2r" ,  8L    , "-"     ,
    "chr2" , 30L    , 60L  , "d2f" , 16L    , "+"     ,
    "chr2" , 35L    , 65L  , "e2q" , 32L    , "."     ,
    "chr2" , 39L    , 80L  , "f2r" , 64L    , "-"
  )
  b <- tibble::tribble(
    ~chrom , ~start , ~end , ~name  , ~score , ~strand ,
    "chr1" , 10L    ,  50L , "2a1r" ,  2L    , "-"     ,
    "chr1" , 40L    ,  70L , "2b1q" ,  4L    , "."     ,
    "chr1" , 60L    , 100L , "2c1f" ,  8L    , "+"     ,
    "chr2" , 15L    ,  40L , "2d2f" , 16L    , "+"     ,
    "chr2" , 30L    , 100L , "2e2r" , 32L    , "-"
  )
  res <- bed_jaccard(a, b)
  expect_equal(res$len_i, 145)
  expect_equal(res$len_u, 325)
  expect_equal(round(res$jaccard, 5), round(0.8055556, 5))
  expect_equal(res$n, 2)
})