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

test_that(desc, code)

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

code | test code containing expectations |

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.

test_that("trigonometric functions match identities", { expect_equal(sin(pi / 4), 1 / sqrt(2)) expect_equal(cos(pi / 4), 1 / sqrt(2)) expect_equal(tan(pi / 4), 1) }) # Failing test: if (FALSE) { test_that("trigonometric functions match identities", { expect_equal(sin(pi / 4), 1) }) }