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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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Version

Install

install.packages('testthat')

Monthly Downloads

421,135

Version

3.2.3

License

MIT + file LICENSE

Issues

Pull Requests

Stars

Forks

Repository

https://github.com/r-lib/testthat

Homepage

https://testthat.r-lib.org

Maintainer

Hadley Wickham

Last Published

January 13th, 2025

Functions in testthat (3.2.3)

auto_test_package

Watches a package for changes, rerunning tests as appropriate.

Provide human-readable comparison of two objects

equality-expectations

Does code return the expected value?

default_reporter

Retrieve the default reporter

context_start_file

Start test context from a file name

SummaryReporter

Test reporter: summary of errors.

Does a string match a regular expression?

describe: a BDD testing language

evaluate_promise

Evaluate a promise, capturing all types of output.

Does code return a vector with the specified length?

Does code return a vector with (given) names?

The building block of all expect_ functions

comparison-expectations

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

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

expect_snapshot_file

Snapshot testing for whole files

expect_invisible

Does code return a visible or invisible object?

Describe the context of a set of tests.

Capture the state of a directory.

expect_known_output

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

Does an object inherit from a given class?

expect_less_than

Deprecated numeric comparison functions

Compare two directory states.

Does code return NULL?

expect_no_error

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

Does code print output to the console?

expect_reference

Does code return a reference to the expected object?

expect_output_file

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

expect_equivalent

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

expect_snapshot_value

Snapshot testing for values

Does code execute silently?

Expect that a condition holds.

Tools for testing expectations

logical-expectations

Does code return TRUE or FALSE?

make_expectation

Make an equality test.

expect_setequal

Does code return a vector containing the expected values?

inheritance-expectations

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

expect_snapshot

Snapshot testing

is_informative_error

Is an error informative?

Default expectations that always succeed or fail.

Construct an expectation object

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

local_test_context

Locally set options for maximal test reproducibility

Quasi-labelling

set_state_inspector

State inspected

Set maximum number of test failures allowed before aborting the run

Negate an expectation

Objects exported from other packages

Old-style expectations.

local_test_directory

Locally set test directory options

Determine testing status

Temporarily change the active testthat edition

snapshot_accept

Snapshot management

Test package examples

reporter-accessors

Get and set active reporter.

Generate default testing environment.

Try evaluating an expressing multiple times until it succeeds.

Find reporter object given name or object.

expect_snapshot_output

Snapshot helpers

find_test_scripts

Find test files

Run tests in a single file

local_mocked_bindings

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

expect_cpp_tests_pass

Do C++ tests past?

Run all tests in a package

local_snapshotter

Instantiate local snapshotting context

Use Catch for C++ Unit Testing

Run code before/after tests

takes_less_than

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

testthat_examples

Retrieve paths to built-in example test files

testthat-package

An R package to make testing fun!

Locate a file in the testing directory

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

Superseded skip functions

Mock functions in a package.

Run code after all test files

Run all tests in a directory

testthat_results

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

testthat_tolerance

Default numeric tolerance

Check reporter: 13 line summary of problems

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

Multi reporter: combine several reporters in one.

ProgressReporter

Test reporter: interactive progress bar of errors.

Test reporter: fail at end.

RStudioReporter

Test reporter: RStudio

MinimalReporter

Test reporter: minimal.

LocationReporter

Test reporter: location

Test reporter: summary of errors in jUnit XML format.

Test reporter: start recovery.

capture_condition

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

Test reporter: gather all errors silently.

Test reporter: stop on error

TeamcityReporter

Test reporter: Teamcity format.

Test reporter: TAP format.

Capture output to console

Manage test reporting

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