tests/testthat/test-dshw.R

In forecast: Forecasting Functions for Time Series and Linear Models

# A unit test for dshw function
test_that("Test dshw()", {
  # Test negative values and period1 and period2 not specified
  set.seed(345)
  expect_error(dshw(-10:10))
  expect_error(dshw(abs(rnorm(100))))
  # Test fits with period1 and period2 swapped
  set.seed(5555)
  t <- seq(0, 1, by = 0.1)
  x <- exp(sin(2 * pi * t) + cos(2 * pi * t * 4) + rnorm(length(t), 0, 0.1))
  fit1 <- dshw(x, period1 = 4, period2 = 2)$mean
  fit2 <- dshw(x, period1 = 2, period2 = 4)$mean
  expect_true(all(fit1 == fit2))
  # Test fits with lambda specified and armethod = FALSE
  y <- x + 1
  fit3 <- dshw(y, period1 = 2, period2 = 4, lambda = 2, biasadj = FALSE)
  fit4 <- dshw(y, period1 = 2, period2 = 4, lambda = 2, biasadj = TRUE)
  expect_false(identical(fit3$mean, fit4$mean))
  fit5 <- dshw(x, period1 = 2, period2 = 4, armethod = FALSE)
  # Test fits with inappropriate periods specified
  expect_error(dshw(x, period1 = 2, period2 = 2))
  expect_error(dshw(x, period1 = 2, period2 = 4.1))
})