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testthat

Overview

Testing your code can be painful and tedious, but it greatly increases the quality of your code. testthat tries to make testing as fun as possible, so that you get a visceral satisfaction from writing tests. Testing should be addictive, so you do it all the time. To make that happen, testthat:

  • Provides functions that make it easy to describe what you expect a function to do, including catching errors, warnings, and messages.

  • Easily integrates in your existing workflow, whether it’s informal testing on the command line, building test suites, or using R CMD check.

  • Displays test progress visually, showing a pass, fail, or error for every expectation. If you’re using the terminal or a recent version of RStudio, it’ll even colour the output.

testthat draws inspiration from the xUnit family of testing packages, as well as from many of the innovative ruby testing libraries, like rspec, testy, bacon and cucumber.

testthat is the most popular unit testing package for R and is used by thousands of CRAN packages.

If you’re not familiar with testthat, the testing chapter in R packages gives a good overview, along with workflow advice and concrete examples.

Installation

# Install the released version from CRAN
install.packages("testthat")

# Or the development version from GitHub:
# install.packages("pak")
pak::pak("r-lib/testthat")

Usage

The easiest way to get started is with usethis. Assuming you’re in a package directory, just run usethis::use_test("name") to create a test file, and set up all the other infrastructure you need. If you’re using RStudio, press Cmd/Ctrl + Shift + T (or run devtools::test() if not) to run all the tests in a package.

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Install

install.packages('testthat')

Monthly Downloads

429,916

Version

3.2.1

License

MIT + file LICENSE

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Maintainer

Last Published

December 2nd, 2023

Functions in testthat (3.2.1)

compare

Provide human-readable comparison of two objects
comparison-expectations

Does code return a number greater/less than the expected value?
expect_is

Does an object inherit from a given class?
describe

describe: a BDD testing language
TeamcityReporter

Test reporter: Teamcity format.
expect

The building block of all expect_ functions
dir_state

Capture the state of a directory.
expect_equivalent

Is an object equal to the expected value, ignoring attributes?
context_start_file

Start test context from a file name
expect_known_output

Expectations: is the output or the value equal to a known good value?
default_reporter

Retrieve the default reporter
expect_invisible

Does code return a visible or invisible object?
expect_length

Does code return a vector with the specified length?
expect_snapshot

Snapshot testing
expect_error

Does code throw an error, warning, message, or other condition?
context

Describe the context of a set of tests.
expect_silent

Does code execute silently?
expect_less_than

Deprecated numeric comparison functions
compare_state

Compare two directory states.
expect_named

Does code return a vector with (given) names?
expect_no_error

Does code run without error, warning, message, or other condition?
expect_output

Does code print output to the console?
expect_match

Does a string match a regular expression?
expect_null

Does code return NULL?
equality-expectations

Does code return the expected value?
evaluate_promise

Evaluate a promise, capturing all types of output.
expect_setequal

Does code return a vector containing the expected values?
fail

Default expectations that always succeed or fail.
expect_snapshot_value

Snapshot testing for values
expect_reference

Does code return a reference to the expected object?
expectation

Construct an expectation object
expect_snapshot_file

Snapshot testing for whole files
expect_output_file

Expectations: is the output or the value equal to a known good value?
find_reporter

Find reporter object given name or object.
find_test_scripts

Find test files
logical-expectations

Does code return TRUE or FALSE?
make_expectation

Make an equality test.
quasi_label

Quasi-labelling
expect_snapshot_output

Snapshot helpers
expect_vector

Does code return a vector with the expected size and/or prototype?
is_testing

Determine testing status
snapshot_accept

Snapshot management
local_snapshotter

Instantiate local snapshotting context
expect_success

Tools for testing expectations
source_file

Source a file, directory of files, or various important subsets
local_mocked_bindings

Mocking tools
expect_that

Expect that a condition holds.
local_edition

Temporarily change the active testthat edition
set_state_inspector

State inspected
teardown_env

Run code after all test files
test_path

Locate a file in the testing directory
test_that

Run a test
test_dir

Run all tests in a directory
oldskool

Old-style expectations.
set_max_fails

Set maximum number of test failures allowed before aborting the run
reexports

Objects exported from other packages
not

Negate an expectation
skip

Skip a test
skip_on_travis

Superseded skip functions
takes_less_than

Does code take less than the expected amount of time to run?
inheritance-expectations

Does code return an object inheriting from the expected base type, S3 class, or S4 class?
verify_output

Verify output
with_mock

Mock functions in a package.
test_file

Run tests in a single file
test_package

Run all tests in a package
test_env

Generate default testing environment.
local_test_context

Locally set options for maximal test reproducibility
is_informative_error

Is an error informative?
local_test_directory

Locally set test directory options
teardown

Run code before/after tests
watch

Watch a directory for changes (additions, deletions & modifications).
expect_cpp_tests_pass

Do C++ tests past?
testthat_examples

Retrieve paths to built-in example test files
reporter-accessors

Get and set active reporter.
testthat_tolerance

Default numeric tolerance
testthat-package

An R package to make testing fun!
test_examples

Test package examples
testthat_results

Create a testthat_results object from the test results as stored in the ListReporter results field.
use_catch

Use Catch for C++ Unit Testing
try_again

Try evaluating an expressing multiple times until it succeeds.
RStudioReporter

Test reporter: RStudio
MinimalReporter

Test reporter: minimal.
ListReporter

List reporter: gather all test results along with elapsed time and file information.
CheckReporter

Check reporter: 13 line summary of problems
MultiReporter

Multi reporter: combine several reporters in one.
JunitReporter

Test reporter: summary of errors in jUnit XML format.
DebugReporter

Test reporter: start recovery.
FailReporter

Test reporter: fail at end.
LocationReporter

Test reporter: location
ProgressReporter

Test reporter: interactive progress bar of errors.
capture_condition

Capture conditions, including messages, warnings, expectations, and errors.
capture_output

Capture output to console
TapReporter

Test reporter: TAP format.
StopReporter

Test reporter: stop on error
SummaryReporter

Test reporter: summary of errors.
SilentReporter

Test reporter: gather all errors silently.
Reporter

Manage test reporting
auto_test

Watches code and tests for changes, rerunning tests as appropriate.
auto_test_package

Watches a package for changes, rerunning tests as appropriate.