tests/testthat/test-calc_target_capacity.R

In NHSRwaitinglist: Waiting List Metrics Using Queuing Theory

test_that("wrong input class causes an error", {
  msg_fragment <- "must be of class"
  expect_error(calc_target_capacity("x", 2, 3, 4, 5), msg_fragment)
  expect_error(calc_target_capacity(1, "x", 3, 4, 5), msg_fragment)
  expect_error(calc_target_capacity(1, 2, "x", 4, 5), msg_fragment)
  expect_error(calc_target_capacity(1, 2, 3, "x", 5), msg_fragment)
  expect_error(calc_target_capacity(1, 2, 3, 4, "x"), msg_fragment)
})

test_that("it returns expected result with fixed single values vs arithmetic", {
  em <- "calc_target_capacity(): arithmetic error with single value inputs."
  expect_equal(
    calc_target_capacity(30, 52, 3, 1.1, 1.2),
    30 + (((1.1^2 + 1.2^2) / 2) * (3 / 52))
  )
})

test_that("it returns an expected result with fixed single values", {
  em <- "calc_target_capacity(): arithmetic error with single value inputs."
  expect_equal(calc_target_capacity(30, 52, 3, 1.1, 1.2), 30.076442)
})

test_that("it returns an expected result with vector of fixed values", {
  em <- "calc_target_capacity(): arithmetic error with vector of input values."
  expect_equal(
    calc_target_capacity(
      c(30, 42, 35),
      c(52, 65, 50),
      c(3, 2, 1),
      c(1.1, 1.2, 1.3),
      c(1.4, 1.5, 1.6)
    ),
    c(30.0914423, 42.0567692, 35.0425)
  )
})


test_that("it returns the same length output as provided on input", {
  n <- round(runif(1, 0, 30))
  in1 <- rnorm(n = n, 50, 20)
  in2 <- in1 * runif(1, 0.5, 1.5)
  em <- "calc_target_capacity(): output vector length != input vector length."
  expect_length(calc_target_capacity(in1, in2), length(in1))
})