genome <- tibble::tribble(
  ~chrom , ~size ,
  "chr1" ,  1000 ,
  "chr2" ,  1000
)

x <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,     50 ,   75 ,
  "chr1" ,    250 ,  400 ,
  "chr1" ,    500 ,  600
)

y <- tibble::tribble(
  ~chrom , ~start , ~end ,
  "chr1" ,    100 ,  200 ,
  "chr1" ,    200 ,  800
)

bed_projection(x, y, genome)
bed_projection(x, y, genome, by_chrom = TRUE)

test_that("basic projection test works", {
  # compare output to pbinom( )function
  # 2 of 3 hits, 7 of 10 chance
  # 1- pbinom because pval > .5

  exp <- 1 - pbinom(2, 3, 7 / 10)
  res <- bed_projection(x, y, genome)
  expect_equal(res$p.value, exp)
})

test_that("projection per chromosome works (by_chrom = TRUE)", {
  genome <- tibble::tribble(
    ~chrom , ~size ,
    "chr1" ,  2000 ,
    "chr2" ,  2000
  )

  x <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,    100 ,  200 ,
    "chr1" ,    250 ,  400 ,
    "chr1" ,    500 ,  600 ,
    "chr1" ,   1000 , 2000 ,
    "chr2" ,    100 ,  200
  )

  y <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,    150 ,  175 ,
    "chr1" ,    525 ,  575 ,
    "chr1" ,   1100 , 1200 ,
    "chr1" ,   1400 , 1600 ,
    "chr2" ,    100 , 1500
  )
  res <- bed_projection(x, y, genome, by_chrom = TRUE)
  expect_true(all(c("chr1", "chr2") %in% res$chrom))
})

test_that("report significant when intervals are underrepresented, .lower_tail = TRUE", {
  sig <- pbinom(0, 4, .7)

  genome <- tibble::tribble(
    ~chrom , ~size ,
    "chr1" ,  1000 ,
    "chr2" ,  1000
  )

  x <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,     10 ,   20 ,
    "chr1" ,     25 ,   40 ,
    "chr1" ,     50 ,   60 ,
    "chr1" ,    100 ,  150
  )

  y <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,    200 ,  275 ,
    "chr1" ,    525 ,  575 ,
    "chr1" ,    200 ,  900
  )
  res <- bed_projection(x, y, genome)
  expect_true(res$lower_tail == TRUE)
  expect_true(res$p.value < .5)
  expect_true(res$p.value == sig)
})

test_that("report significant when intervals are overrepresented, .lower_tail = FALSE", {
  sig <- 1 - pbinom(4, 4, .7)
  genome <- tibble::tribble(
    ~chrom , ~size ,
    "chr1" ,  1000 ,
    "chr2" ,  1000
  )

  x <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,    200 ,  225 ,
    "chr1" ,    250 ,  400 ,
    "chr1" ,    500 ,  600 ,
    "chr1" ,    300 ,  350
  )

  y <- tibble::tribble(
    ~chrom , ~start , ~end ,
    "chr1" ,    200 ,  275 ,
    "chr1" ,    525 ,  575 ,
    "chr1" ,    200 ,  900
  )
  res <- bed_projection(x, y, genome)
  expect_true(res$lower_tail == FALSE)
  expect_true(res$p.value < .5)
  expect_true(res$p.value == sig)
})