tests/testthat/test-get_breaks.R

In cheapr: Simple Functions to Save Time and Memory

test_that("breaks", {
  x <- 1:20

  b1 <- function(x, n){
   get_breaks(x, n, expand_min = FALSE, expand_max = FALSE)
  }

  b2 <- function(x, n){
    get_breaks(x, n, expand_min = FALSE, expand_max = TRUE)
  }

  b3 <- function(x, n){
    get_breaks(x, n, expand_min = FALSE, expand_max = FALSE, pretty = FALSE)
  }

  expect_equal(b1(x, 5), seq(0, 20, 5))
  expect_equal(b2(x, 5), seq(0, 25, 5))

  expect_equal(b1(1:10, 5), seq(1, 9, 2))
  expect_equal(b2(1:10, 5), seq(1, 11, 2))

  expect_equal(b1(1:10, 20), seq(1, 10, 0.5))
  expect_equal(b2(1:10, 20), seq(1, 10.5, 0.5))

  expect_equal(b3(1:10, 20), seq(1, 10, 9/20))
  expect_equal(b3(1:10, 10), seq(1, 10, 9/10))
  expect_equal(b3(1:17, 13), seq(1, 17, 16/13))

  expect_equal(
    get_breaks(0:10, pretty = FALSE, expand_min = TRUE, expand_max = TRUE,
               n = 7),
    seq(0 - (10/7), 10 + (10/7), 10/7)
  )

  expect_equal(
    b1(with_local_seed(rnorm(100), .seed = 42), 13),
    seq(-3, 2, 0.5)
  )


  expect_equal(
    b1(seq(-0.034, 123, 0.5), 10),
    seq(-30, 120, 30)
  )

  expect_equal(get_breaks(1:30, 3), seq(0, 40, 10))
  expect_equal(get_breaks(1:30, 5), seq(0, 40, 10))

  # Zero range

  expect_equal(b1(123, 7), seq(123 - 123/1000, 123 + 123/1000, length.out = 8))

  # Lots of breaks


  expect_equal(
    b2(with_local_seed(rnorm(100), 42), 123456),
    seq(-2.99310, 2.28665, 0.00005)
  )

  y <- with_local_seed(rnorm(100, sd = 0.03), 43)

  y_min <- min(y)
  y_max <- max(y)

  expect_true(max(get_breaks(y, 10^3, expand_max = FALSE)) <= y_max)
  expect_true(max(get_breaks(y, 10^3, expand_max = TRUE)) > y_max)

  expect_false(min(get_breaks(y, 10^3, expand_min = FALSE)) > y_min)
  expect_false(min(get_breaks(y, 10^3, expand_min = TRUE)) > y_min)

  expect_true(min(get_breaks(y, 10^3, expand_min = FALSE)) <= y_min)
  expect_true(min(get_breaks(y, 10^3, expand_min = TRUE)) < y_min)

  # Floating point precision example

  expect_identical(
    get_breaks(with_local_seed(rnorm(100, sd = 0.01), .seed = 3), 10),
    seq(-25L, 20L, 5L) / 1000
  )

  # Another

  # seq(-2.8, 3.1, by = 0.1) This is basically the result, which has FP error

  expect_identical(
    get_breaks(with_local_seed(rnorm(1e03), 2), 100),
    seq(-28L, 31L, by = 1L) / 10
  )

  expect_equal(
    get_breaks(with_local_seed(rnorm(100, sd = 1e-12), 1), 15, expand_max = TRUE),
    seq(-2.5e-12, 2.5e-12, length.out = 11)
  )
})