testthat¶

The standard testing framework for R packages. Scrutin auto-detects testthat when a DESCRIPTION file and a tests/testthat/ directory are both present.

Installing testthat¶

testthat is not shipped with Scrutin. Install it from CRAN:

install.packages("testthat")

Directory structure¶

mypackage/
├── DESCRIPTION
├── NAMESPACE
├── R/
│   └── math.R
└── tests/
    └── testthat/
        └── test-math.R

Minimal example¶

R/math.R

#' @export
add <- function(x, y) x + y

tests/testthat/test-math.R

test_that("add works", {
  expect_equal(add(2, 3), 5)
  expect_equal(add(-1, 1), 0)
})

Running¶

scrutin mypackage              # TUI
scrutin -r plain mypackage     # text output

Configuration¶

No configuration is required. To override defaults in .scrutin/config.toml:

[[suite]]
tool = "testthat"
# defaults pick up tests/testthat/**/test-*.R and watch R/**/*.R

# Override explicitly if needed:
# run   = ["tests/testthat/**/test-*.R"]
# watch = ["R/**/*.R"]

Working directory¶

Scrutin runs workers from the suite root (the directory containing DESCRIPTION, which in a single-package project equals the project root; in a monorepo use [[suite]] root = "r" or similar). The subprocess CWD is the suite root. testthat::test_path() is the portable way to build paths to fixture files:

test_that("reads fixture data", {
  d <- read.csv(test_path("fixtures", "data.csv"))
  expect_equal(nrow(d), 10)
})

Bare relative paths like "inst/extdata/data.csv" resolve against the suite root, which makes them portable between Scrutin and interactive devtools::load_all() sessions.

Package loading¶

Workers call pkgload::load_all() to load the package. When a source file changes in watch mode, the engine reloads the package automatically before running affected tests. If you add or change @export or @importFrom tags, run devtools::document() separately: Scrutin does not invoke roxygen.

Custom runner¶

scrutin init writes the default runner to .scrutin/runners/testthat.R. Edit that file in place: the engine automatically prefers it over the embedded default whenever it exists, no config change needed. To point at a different path (e.g. a shared runner in a sibling directory), set runner on an explicit suite:

[[suite]]
tool   = "testthat"
runner = "shared/testthat-runner.R"