# test_that {testthat}

### Description

A test encapsulates a series of expectations about small, self-contained set of functionality. Each test is contained in a context and contains multiple expectation generated by `expect_that`

.

### Usage

test_that(desc, code)

### Arguments

- desc
- test name. Names should be kept as brief as possible, as they are often used as line prefixes.
- code
- test code containing expectations

### Details

Tests are evaluated in their own environments, and should not affect global state.

When run from the command line, tests return `NULL`

if all expectations are met, otherwise it raises an error.

### Examples

test_that("trigonometric functions match identities", { expect_that(sin(pi / 4), equals(1 / sqrt(2))) expect_that(cos(pi / 4), equals(1 / sqrt(2))) expect_that(tan(pi / 4), equals(1)) }) # Failing test: ## Not run: test_that("trigonometric functions match identities", { expect_that(sin(pi / 4), equals(1)) }) ## End(Not run)

Documentation reproduced from package testthat, version 0.8.1. License: MIT + file LICENSE