tests/testthat/test-strata_rs.R

In randomizr: Easy-to-Use Tools for Common Forms of Random Assignment and Sampling

context("Stratified Random Sampling")

strata <- rep(c("A", "B", "C"), times = c(50, 100, 200))


# Errors ------------------------------------------------------------------

expect_error(strata_rs(strata = strata, strata_prob = c(.1, .2, .3, .4)))
expect_error(strata_rs(strata = strata, strata_prob = c(.1, .2,-.3)))
expect_error(strata_rs(strata = strata, strata_prob = c(.1, .2, 1.1)))
expect_error(strata_rs(strata = strata, strata_n = c(10, 101, 40)))
expect_error(strata_rs(strata = strata, prob = 1.2))
expect_error(strata_rs(strata = strata, prob = -1))

S <- strata_rs(strata = strata)
table(strata, S)
probs <- strata_rs_probabilities(strata = strata)
table(strata, probs)


S <- strata_rs(strata = strata, prob = .5)
table(strata, S)
probs <- strata_rs_probabilities(strata = strata, prob = .5)
table(strata, probs)

S <- strata_rs(strata = strata, prob = 1)
table(strata, S)
probs <- strata_rs_probabilities(strata = strata, prob = 1)
table(strata, probs)


S <- strata_rs(strata = strata, prob = 0)
table(strata, S)
probs <- strata_rs_probabilities(strata = strata, prob = 0)
table(strata, probs)


S <- strata_rs(strata = strata, prob = .33)
table(strata, S)
probs <- strata_rs_probabilities(strata = strata, prob = .33)
table(strata, probs)

S <- strata_rs(strata = strata, strata_n = c(20, 30, 40))
table(strata, S)
probs <-
  strata_rs_probabilities(strata = strata, strata_n = c(20, 30, 40))
table(strata, probs)

S <- strata_rs(strata = strata, strata_prob = c(.1, .2, .3))
table(strata, S)
probs <-
  strata_rs_probabilities(strata = strata, strata_prob = c(.1, .2, .3))
table(strata, probs)

S <- strata_rs(strata = strata, strata_prob = c(0, .2, .3))
table(strata, S)
probs <-
  strata_rs_probabilities(strata = strata, strata_prob = c(0, .2, .3))
table(strata, probs)



test_that("Unhandled cases warn", {
  expect_warning(strata_rs_probabilities(
    strata = gl(2, 999),
    strata_prob = c("0.5", "0.5")
  ))
  
})


test_that("prob_unit and n_unit", {
  strata <- rep(c("A", "B", "C"), times = c(50, 100, 200))
  
  S <- strata_rs(strata = strata, prob_unit = rep(c(.1, .2, .3), c(50, 100, 200)))
  
  expect_equal(table(strata, S),
               structure(
                 c(45L, 80L, 140L, 5L, 20L, 60L),
                 .Dim = 3:2,
                 .Dimnames = list(strata = c("A", "B", "C"), S = c("0", "1")),
                 class = "table"
               ))
  
  expect_error(
    strata_rs(strata = strata, prob_unit = rep(c(.1, .2, .3), c(200, 100, 50))),
    "In a stratified random assignment design, `prob_unit` must be the same for all units within the same stratum."
  )
  
  
  S <- strata_rs(strata = strata, n_unit = rep(c(20, 20, 25), c(50, 100, 200)))
  
  expect_equal(table(strata, S), 
               structure(c(30L, 80L, 175L, 20L, 20L, 25L), .Dim = 3:2, .Dimnames = list(
                 strata = c("A", "B", "C"), S = c("0", "1")), class = "table"))
  
  expect_error(
    strata_rs(strata = strata, n_unit = rep(c(20, 20, 25), c(200, 100, 50))),
    "In a stratified random sampling design, `n_unit` must be the same for all units within the same stratum."
  )
  
})