In stephlocke/Rtraining: Training Materials on R

Develop R

Utility packages

• testthat
• devtools (useful for other things)
• microbenchmark
• packrat

Package development

library(devtools)
pkg<-"newPackage"
create(pkg)

library(devtools) # Open the project!
add_test_infrastructure() # Add unit test framework
add_travis() # Add CI framework
use_vignette() # Add folder for macro-level help files
use_package_doc() # Add file for providing info about your package
use_readme_rmd() # Make a README!

What to unit test

1. A single set of values that represent "normal" and expect this matches a correct answer
2. A dataset that represents "normal" and expecting this to match correct answers
3. Various permutations of bad input values and expect errors (ideally specific error messages)
4. Edge cases that cover extreme values or boundaries for any inequalities or conditions
5. Any bugs or compatibility issues

How to test

myfunc<-function(a=1,b=2,c="blah"){
stopifnot(is.numeric(a), is.numeric(b), is.character(c))
d<-ifelse(a<0,a*b,a/b)
e<-paste0(c,d)
return(e)
}
library(testthat)
# Add a high-level name for group of tests, typically the function name
context("myfunc")

# Simplest test
test_that("Defaults return expected result",{
  result<-myfunc()
  check<-"blah0.5"
  expect_equal(result,check)
})

Next steps

1. Read Hadley's Package Development guide
2. Practice!

stephlocke/Rtraining documentation built on May 30, 2019, 3:36 p.m.