tests/testthat/test-merge_strata.R

In optimall: Allocate Samples Among Strata

context("test-merge_strata")

library(dplyr)
library(optimall)

# Make data

set.seed(354)
data <- data.frame(
  "strata" = rep(c("A", "B", "C"), times = 10),
  "y" = rnorm(30)
)

test_that("merge_strata produces a dataframe with the same number of
          rows as input and one more column called 'new_strata' with
          only the specified strata changed", {
  output <- merge_strata(data,
    strata = "strata",
    merge = c("A", "B"), name = "new"
  )
  expect_equal(all(dplyr::select(output, -new_strata) == data), TRUE)
  expect_equal(as.vector(table(output$new_strata)), c(10, 20))
  expect_equal(unique(dplyr::filter(
    output,
    old_strata %in%
      c("A", "B")
  )$new_strata), "new")
})

test_that("error messages properly address issues with inputs", {
  expect_error(
    merge_strata(data,
      strata = "wrong",
      merge = c("A", "B"), name = "new"
    ),
    "'strata' must be a string or vector of strings"
  )
  expect_error(
    merge_strata(data,
      strata = "strata",
      merge = c("A", "D"), name = "new"
    ),
    "names in 'merge' must each exactly match at least"
  )
})

test_that("error messages properly address issues with inputs", {
  expect_error(
    merge_strata(data,
      strata = "wrong",
      merge = c("A", "B"), name = "new"
    ),
    "'strata' must be a string or vector of strings"
  )
  expect_error(
    merge_strata(data,
      strata = "strata",
      merge = c("A", "D"), name = "new"
    ),
    "names in 'merge' must each exactly match at least"
  )
})

test_that("giving NULL name works", {
  expect_equal(
    unique((merge_strata(
      data,
      "strata", c("A", "B")
    )$new_strata)),
    c("A.B", "C")
  )
})

test_that("errors work", {
  data$strata2 <- rep(c(1, 2), times = 15)
  expect_error(
    merge_strata(data, c("strata", "strata2"), c("A", "B")),
    "'strata' should specify only one column"
  )
  expect_error(
    merge_strata(data, strata = "strata", merge = NULL),
    "Expecting names of strata to merge"
  )
  x <- c(1, 2, 3)
  expect_error(
    merge_strata(
      data = x, "strata",
      merge = c(1, 2)
    ),
    "must be a dataframe or matrix"
  )
})