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This function is the low-level workhorse that powers test_local() and test_package(). Generally, you should not call this function directly. In particular, you are responsible for ensuring that the functions to test are available in the test env (e.g. via load_package).


  filter = NULL,
  reporter = NULL,
  env = NULL,
  load_helpers = TRUE,
  stop_on_failure = TRUE,
  stop_on_warning = FALSE,
  wrap = lifecycle::deprecated(),
  package = NULL,
  load_package = c("none", "installed", "source")



Path to directory containing tests.


If not NULL, only tests with file names matching this regular expression will be executed. Matching is performed on the file name after it's stripped of "test-" and ".R".


Reporter to use to summarise output. Can be supplied as a string (e.g. "summary") or as an R6 object (e.g. SummaryReporter$new()).

See Reporter for more details and a list of built-in reporters.


Environment in which to execute the tests. Expert use only.


Additional arguments passed to grepl() to control filtering.


Source helper files before running the tests? See source_test_helpers() for more details.


If TRUE, throw an error if any tests fail.


If TRUE, throw an error if any tests generate warnings.




If these tests belong to a package, the name of the package.


Strategy to use for load package code:

  • "none", the default, doesn't load the package.

  • "installed", uses library() to load an installed package.

  • "source", uses pkgload::load_all() to a source package.


A list (invisibly) containing data about the test results.

Special files

There are two types of .R file that have special behaviour:

  • Test files start with test and are executed in alphabetical order.

  • Setup files start with setup and are executed before tests. If clean up is needed after all tests have been run, you can use withr::defer(clean_up(), teardown_env()). See vignette("test-fixtures") for more details.

There are two other types of special file that we no longer recommend using:

  • Helper files start with helper and are executed before tests are run. They're also loaded by devtools::load_all(), so there's no real point to them and you should just put your helper code in R/.

  • Teardown files start with teardown and are executed after the tests are run. Now we recommend interleave setup and cleanup code in setup- files, making it easier to check that you automatically clean up every mess that you make.

All other files are ignored by testthat.


Each test is run in a clean environment to keep tests as isolated as possible. For package tests, that environment that inherits from the package's namespace environment, so that tests can access internal functions and objects.