test_that("fails correctly with out-of-range values", {
   expect_error(
      sampling_transects(n_quadrats = 2L,
                         xmin = 0, xmax = 1,
                         ymin = 0, ymax = 1,
                         x0 = 0, y0 = 0, delta_x = 1, delta_y = 0.1,
                         quadrat_size = sqrt(0.01)
      )
   )

   expect_error(
      sampling_transects(n_quadrats = 2L,
                         xmin = 0, xmax = 1,
                         ymin = 0, ymax = 1,
                         x0 = 0, y0 = 0, delta_x = 0.1, delta_y = 1,
                         quadrat_size = sqrt(0.01)
      )
   )

   expect_warning(
      sampling_transects(n_quadrats = 10L,
                         xmin = 0, xmax = 1,
                         ymin = 0, ymax = 1,
                         x0 = 0.4, y0 = 0.4, delta_x = 0.01, delta_y = 0.01,
                         quadrat_size = 0.1
      )
   )
})


test_that("classes are correct", {
   expect_type(
      sampling_transects(n_quadrats = 2L,
                         xmin = 0, xmax = 1,
                         ymin = 0, ymax = 1,
                         x0 = 0, y0 = 0, delta_x = 0.1, delta_y = 0.1,
                         quadrat_size = 0.01
      ), "list")
   expect_s3_class(
      sampling_transects(n_quadrats = 2L,
                         xmin = 0, xmax = 1,
                         ymin = 0, ymax = 1,
                         x0 = 0, y0 = 0, delta_x = 0.1, delta_y = 0.1,
                         quadrat_size = 0.01
      ), "data.frame")
})

test_that("dimensions are correct", {
   n_quadrats = 5L
   xy_dat <- sampling_transects(n_quadrats = n_quadrats,
                                xmin = 0, xmax = 1,
                                ymin = 0, ymax = 1,
                                x0 = 0, y0 = 0, delta_x = 0.1, delta_y = 0.1,
                                quadrat_size = 0.01
   )

   expect_equal(dim(xy_dat), c(n_quadrats, 2L))
})

test_that("samples are within range", {
   xmin = 0
   xmax = 1
   ymin = 0
   ymax = 1
   quadrat_size =  0.01

   xy_dat <- sampling_transects(n_quadrats = 5L,
                                xmin = xmin, xmax = xmax,
                                ymin = ymin, ymax = ymax,
                                x0 = 0, y0 = 0, delta_x = 0.1, delta_y = 0.1,
                                quadrat_size = quadrat_size
   )

   expect_gte(min(xy_dat$x), xmin)
   expect_lte(max(xy_dat$x) + quadrat_size, xmax)
   expect_gte(min(xy_dat$y), ymin)
   expect_lte(max(xy_dat$y) + quadrat_size, ymax)
})