test_that("compare state works correctly", {
  loc <- withr::local_tempfile(pattern = "watcher")
  dir.create(loc)

  empty <- dir_state(loc)
  expect_equal(length(empty), 0)

  file.create(file.path(loc, "test-1.txt"))
  one <- dir_state(loc)
  expect_equal(length(one), 1)
  expect_equal(basename(names(one)), "test-1.txt")

  diff <- compare_state(empty, one)
  expect_equal(diff$n, 1)
  expect_equal(basename(diff$added), "test-1.txt")

  write.table(mtcars, file.path(loc, "test-1.txt"))
  diff <- compare_state(one, dir_state(loc))
  expect_equal(diff$n, 1)
  expect_equal(basename(diff$modified), "test-1.txt")

  file.rename(file.path(loc, "test-1.txt"), file.path(loc, "test-2.txt"))
  diff <- compare_state(one, dir_state(loc))
  expect_equal(diff$n, 2)
  expect_equal(basename(diff$deleted), "test-1.txt")
  expect_equal(basename(diff$added), "test-2.txt")

  diff <- compare_state(
    c(file1 = "62da2", file2 = "e14a6", file3 = "6e6dd"),
    c(file1 = "62da2", file2 = "e14a6", file21 = "532fa", file3 = "3f4sa")
  )
  expect_equal(diff$n, 2)
  expect_equal(basename(diff$added), "file21")
  expect_equal(basename(diff$modified), "file3")
})

test_that("watcher works correctly", {
  skip_on_ci()
  skip_on_os("windows")
  skip_on_cran()
  if (Sys.which("bash") == "") {
    skip("bash not available")
  }
  if (system("bash -c 'which touch'", ignore.stdout = TRUE) != 0L) {
    skip("touch (or which) not available")
  }

  loc <- withr::local_tempfile(pattern = "watcher")
  dir.create(loc)

  code_path <- file.path(loc, "R")
  test_path <- file.path(loc, "tests")

  dir.create(code_path)
  dir.create(test_path)

  delayed.bash.cmd <- function(command) {
    system(paste0("bash -c 'sleep 1;", command, "'"), wait = FALSE)
  }

  add.code.file <- function(file.name) {
    delayed.bash.cmd(paste0("touch ", file.path(code_path, file.name)))
  }

  remove.code.file <- function(file.name) {
    delayed.bash.cmd(paste0("rm ", file.path(code_path, file.name)))
  }

  test.added <- function(added, deleted, modified) {
    expect_equal(length(added), 1)
    expect_equal(grepl("test1.R", added), TRUE)
    expect_equal(length(deleted), 0)
    expect_equal(length(modified), 0)
    FALSE
  }

  test.removed <- function(added, deleted, modified) {
    expect_equal(length(added), 0)
    expect_equal(length(deleted), 1)
    expect_equal(grepl("test1.R", deleted), TRUE)
    expect_equal(length(modified), 0)
    FALSE
  }

  add.code.file("test1.R")
  watch(c(code_path, test_path), test.added)

  remove.code.file("test1.R")
  watch(c(code_path, test_path), test.removed)
})