testthat in R: sourcing in tested files

Question

I am using the testthat package in R and I am trying to test a function defined in a file example.R. This file contains a call source("../utilities/utilities.R") where utilities.R is a file with functions written by me. However, when I am trying to test a function from example.R, sourcing it within the testing script gives the following error:

Error in file(filename, "r", encoding = encoding) : 
  cannot open the connection
In addition: Warning message:
In file(filename, "r", encoding = encoding) :
  cannot open file '../utilities/utilities.R': No such file or directory

Could you please clarify how to run tests for functions in files that source another file?

Tedie

Have you tried putting this file in the same folder? – Majormajordomo

Putting the file to the same directory and sourcing it as source("utilities.R") in example.R does not help: I get a similar error message. – Tedie

Answer 1

Might be a bit late, but I found a solution. Test_that sets the directory holding the test file as the current working directory. See the code below from test-files.r. This causes the working directory to be /tests. Therefore, your main scripts need to source ("../file.R"), which works for testing, but not for running your app.

https://github.com/hadley/testthat/blob/master/R/test-files.r

source_dir <- function(path, pattern = "\\.[rR]$", env = test_env(),
                       chdir = TRUE) {
  files <- normalizePath(sort(dir(path, pattern, full.names = TRUE)))
  if (chdir) {
    old <- setwd(path)
    on.exit(setwd(old))
  }

The solution I found was to add setwd("..") in my test files and simply source the file name without the path. source("file.R") instead of source("../file.R"). Seems to work for me.

Maiamaiah

Since my tests, data, and functions are all in separate folders, I found that I needed to assign the working directory as such wd <- file.path(getwd(),'..') and then specify a functions_dir <- file.path(wd,'functions') and data_dir <- file.path(wd, 'data') inside a helper file. Each test file will then have access to those variables to source their functions and data. – Entice

Answer 2

testthat allows you to define and source helper files (see ?source_test_helpers):

Helper scripts are R scripts accompanying test scripts but prefixed by helper. These scripts are run once before the tests are run.

So what worked perfectly for me is simply putting a file "helper-functions.R" containing the code that I want to source in "/tests/testthat/". You don't have to call source_test_helpers() yourself, testthat will automatically do that when you run tests (e.g., via devtools::test() or testthat::test_dir()).

Sorrow

Answer 3

No great solution to this problem I've found, so far mine has been to set the working directory within each test using the package here.

test_that('working directory is set',{
  setwd(here())
  # test code here
})

Addlebrained

Answer 4

I put the source("C:/Users/.../Utilities.R") in the test file.

Renaterenato