testthat Limitations

testthat doesn’t know how to cleanup:

• The filesystem: creating and deleting files, changing the working directory, etc. -The search path: library(), attach().
• Global options, like options() and par(), and Sys.setenv().

grep("jsonlite", search(), value = TRUE)
#> character(0)
getOption("opt_whatever")
#> NULL
Sys.getenv("envvar_whatever")
#> [1] ""

test_that("landscape changes leak outside the test", {
  library(jsonlite)
  options(opt_whatever = "whatever")
  Sys.setenv(envvar_whatever = "whatever")
  
  expect_match(search(), "jsonlite", all = FALSE)
  expect_equal(getOption("opt_whatever"), "whatever")
  expect_equal(Sys.getenv("envvar_whatever"), "whatever")
})
#> Test passed

grep("jsonlite", search(), value = TRUE)
#> [1] "package:jsonlite"
getOption("opt_whatever")
#> [1] "whatever"
Sys.getenv("envvar_whatever")
#> [1] "whatever"