A lightweight, no-dependency, full-featured package for unit testing
Overview of functionality, or Watch my talk at useR!2021
In R
, do
install.packages("tinytest")
In your (bash) shell, do
git clone https://github.com/markvanderloo/tinytest
cd tinytest
make install
Testing infrastructure must not get in the way of the developer. Setting up
tests should be done with ease. In tinytest
tests are simple R-scripts
where test statements can be interspersed with other code (e.g. to prepare
some results for testing).
The purpose of testing is to gather evidence (data) that builds confidence in the quality of software. Unit tests consist of expressions where an expected result is compared with the result of a program or function. For example:
addOne <- function(x) x + 1
subOne <- function(x) x - 2
# this test should pass
tinytest::expect_equal(addOne(1), 2 )
# this test will fail
tinytest::expect_equal(subOne(2), 1 )
Some unit testing frameworks for R throw a formal exception (error) whenever a test fails. There are several reasons why this is not a good idea.
tinytest
therefore treats test results as data, not as exceptions. This data
can be summarized and investigated by any method you already know in R.
There is a case where the failure of a test should cause an error, namely when
testing for deployment (e.g. publishing a package on CRAN). Therefore, when
running R CMD check
, an error will be thrown if a test has failed. This way
the error interrupts the deployment process instead of the testing process.
By default all tests are run and the results are summarized to one line of output per failed test.
So a package author can request test results from users that installed the package.
Developing and debugging takes focus and often deep concentration. tinytest
supports your workflow by directing you as quickly as possible
to the source of the test failure. In a single line of output you get the
test result, the file and location in the file, and the test call that failed.
Of course, printing is configurable through options.
Keep it simple, keep it clean. See tinyverse.org.