tests/testthat/test-s4-SumsOfBernsteinFunctions.R

In hsloot/rmo: A package for the Marshall-Olkin distribution

bf_sum_of_bfs <- SumOfBernsteinFunctions(
  first = AlphaStableBernsteinFunction(alpha = 0.2497179),
  second = ExponentialBernsteinFunction(lambda = 0.6492033)
)

test_that("Initialize `SumOfBernsteinFunctions`", {
  expect_s4_class(
    bf_sum_of_bfs,
    class = "SumOfBernsteinFunctions"
  )
})

cscale <- sqrt(2)
x <- seq(0, 10, by = 0.25)
actual_fn <- function(x, alpha, lambda) {
  x^alpha + 1 / (1 + lambda / x)
}

test_that("`valueOf` calculates expected values", {
  expect_equal(
    valueOf(bf_sum_of_bfs, x),
    actual_fn(
      x,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda
    )
  )

  expect_equal(
    valueOf(bf_sum_of_bfs, x),
    valueOf0(bf_sum_of_bfs, x)
  )

  expect_equal(
    valueOf(bf_sum_of_bfs, x, cscale = cscale),
    actual_fn(
      cscale * x,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda
    )
  )
})

d <- 7

test_that("`exIntensities` calculates expected values", {
  expect_equal(
    exIntensities(bf_sum_of_bfs, d),
    ex_intensities_naive(
      actual_fn, d,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda
    )
  )

  expect_equal(
    exIntensities(bf_sum_of_bfs, d, cscale = cscale),
    ex_intensities_naive(
      actual_fn, d,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda,
      cscale = cscale
    )
  )

  expect_equal(
    exIntensities(bf_sum_of_bfs, d, cscale = cscale),
    exIntensities(
      bf_sum_of_bfs, d,
      cscale = cscale,
      method = "levy",
      tolerance = testthat_tolerance()
    )
  )

  expect_equal(
    exIntensities(bf_sum_of_bfs, d, cscale = cscale),
    exIntensities(
      bf_sum_of_bfs, d,
      cscale = cscale,
      method = "stieltjes", tolerance = testthat_tolerance()
    )
  )
})

test_that("`exQMatrix` calculates expected values", {
  expect_equal(
    exQMatrix(bf_sum_of_bfs, d),
    ex_qmatrix_naive(
      actual_fn, d,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda
    )
  )

  expect_equal(
    exQMatrix(bf_sum_of_bfs, d, cscale = cscale),
    ex_qmatrix_naive(
      actual_fn, d,
      alpha = bf_sum_of_bfs@first@alpha,
      lambda = bf_sum_of_bfs@second@lambda,
      cscale = cscale
    )
  )

  expect_equal(
    exQMatrix(bf_sum_of_bfs, d, cscale = cscale),
    exQMatrix(
      bf_sum_of_bfs, d,
      cscale = cscale,
      method = "levy", tolerance = testthat_tolerance()
    )
  )

  expect_equal(
    exQMatrix(bf_sum_of_bfs, d, cscale = cscale),
    exQMatrix(
      bf_sum_of_bfs, d,
      cscale = cscale,
      method = "stieltjes", tolerance = testthat_tolerance()
    )
  )
})