naturalsort: Natural Ordering

stopifnot(require(testthat))
context("specification")

library(naturalsort)

test_that("checks naturalorder(decreasing=FALSE, na.last=TRUE)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(5L, 1L, 2L, 3L, 4L)
   actual <- naturalorder(text, decreasing=FALSE, na.last=TRUE)
   expect_that(actual, equals(expected))
})

test_that("checks naturalorder(decreasing=TRUE, na.last=TRUE)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(3L, 2L, 1L, 5L, 4L)
   actual <- naturalorder(text, decreasing=TRUE, na.last=TRUE)
   expect_that(actual, equals(expected))
})

test_that("checks naturalorder(decreasing=FALSE, na.last=FALSE)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(4L, 5L, 1L, 2L, 3L)
   actual <- naturalorder(text, decreasing=FALSE, na.last=FALSE)
   expect_that(actual, equals(expected))
})

test_that("checks naturalorder(decreasing=TRUE, na.last=FALSE)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(4L, 3L, 2L, 1L, 5L)
   actual <- naturalorder(text, decreasing=TRUE, na.last=FALSE)
   expect_that(actual, equals(expected))
})

test_that("checks naturalorder(decreasing=FALSE, na.last=NA)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(5L, 1L, 2L, 3L)
   actual <- naturalorder(text, decreasing=FALSE, na.last=NA)
   expect_that(actual, equals(expected))
})

test_that("checks naturalorder(decreasing=TRUE, na.last=NA)", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c(3L, 2L, 1L, 5L)
   actual <- naturalorder(text, decreasing=TRUE, na.last=NA)
   expect_that(actual, equals(expected))
})

test_that("naturalorder(decreasing=NA) throws an error", {
   expect_that(naturalorder(decreasing=NA), throws_error())
})

test_that("naturalorder for one-character-length vector", {
   text <- c("a", NA, "1")
   expected <- order(text)
   actual <- naturalorder(text)
   expect_that(actual, equals(expected))
})

test_that("naturalorder is stable", {
   text <- c("01", "1", "001", "1", "01")
   expected <- c(3L, 1L, 5L, 2L, 4L)
   actual <- naturalorder(text)
   expect_that(actual, equals(expected))
})

test_that("checks naturalsort() with default parameters", {
   text <- c("a1.png", "a2.png", "a10.png", NA, "a1-1.png")
   expected <- c("a1-1.png", "a1.png", "a2.png", "a10.png")  # na.last=NA by default
   actual <- naturalsort(text)
   expect_that(actual, equals(expected))
})

test_that("naturalfactor() without levels", {
   text <- c("a1.png", "a2.png", "a10.png")
   expected <- c("a1.png", "a2.png", "a10.png")
   f <- naturalfactor(text)
   actual <- levels(f)
   expect_that(actual, equals(expected))
})

test_that("naturalfactor() with levels", {
   text <- c("a1.png", "a2.png", "a10.png")
   levels <- c("a1.png", "a10.png")
   expected_factors <- c("a1.png", NA, "a10.png")
   f <- naturalfactor(text, levels = levels)
   expect_that(levels(f), equals(levels))
   expect_that(as.character(f), equals(expected_factors))
})