test_that("prop_miss handles 0 cases as I expect",{

  expect_equal(prop_miss(0), 0)
  expect_equal(prop_miss(TRUE), 0)
  expect_equal(prop_miss(numeric(0)),NaN)

  expect_equal(prop_miss(iris[0]),NaN)

})

test_that("prop_miss correctly counts the proportion of missings",{
  expect_equal(prop_miss(c(0,NA,120,NA)),0.5)
  expect_equal(prop_miss(c(NA,NA,120,NA)),0.75)
  expect_equal(prop_miss(c(NA,NA,NA,NA)),1)
  expect_equal(prop_miss(c(1,2,3,4,5)),0)
})

test_that("prop_miss works for dataframes",{
  expect_true(dplyr::near(round(prop_miss(airquality),5), 0.047930))
})