Unit Testing with testthat

Introduction

testthat provides unit testing for R. It ensures code works correctly and prevents regressions.

Setup

install.packages("testthat")
library(testthat)

Basic Tests

test_that("description", {
  expect_equal(1 + 1, 2)
  expect_true(TRUE)
  expect_false(FALSE)
})

Expectations

# Equality
expect_equal(actual, expected)
expect_identical(actual, expected)

# Comparisons
expect_gt(x, 5)
expect_lt(x, 5)
expect_gte(x, 5)
expect_lte(x, 5)

# Types
expect_is(x, "data.frame")
expect_type(x, "double")

# Strings
expect_match(x, "pattern")
expectgrep(x, "pattern")

Test Files

# Run tests
test_dir("tests/testthat")

# Run specific file
test_file("tests/testthat/test-file.R")

Summary

Unit tests ensure code correctness. Write tests for all important functions.