Testthat: `library` before `context` throws error?

[alexpghayes]

Hoping this is reproducible:

1. Created a new R package (via new project) using RStudio.
2. usethis::use_testthat()
3. usethis::use_test("example")
4. Modify test-example.R to

library(dplyr)

context("test-example.R")

test_that("multiplication works", {
  expect_equal(2 * 2, 4)
})

1. devtools::test() gives

> devtools::test()
Loading tmp2
Testing tmp2
√ | OK F W S | Context
Error in x[[method]](...) : attempt to apply non-function

== Results =====================================================================
Duration: 0.2 s

OK:       0
Failed:   2
Warnings: 1
Skipped:  0

but if the context comes before library in test-example.R, everything works. Is this expected? I'm using testthat 2.0.0.

[hadley]

I'd say yes, context() should always be the first line.

[hadley]

Re-opening because this bug is super confusing

[gm209]

Hi Chaps,

Did this one get resolved? I am still experiencing this issue.

Cheers

[victordavisyieldsio]

I didn't have a "context()" line in any of my tests either. Adding a context() line as the first line of each of my test-*.R scripts fixed this issue for me. No more "Error in x[method] : attempt to apply non-function" error.

[ctberthiaume]

Is there any way to update the example code in the "Testing" chapter of "R packages" (http://r-pkgs.had.co.nz/tests.html)? It currently has a context call after a library call. This chapter is linked to from the testthat README.md so it's a natural place to look for introductory documentation.

library(stringr)
context("String length")

test_that("str_length is number of characters", {
  expect_equal(str_length("a"), 1)
  expect_equal(str_length("ab"), 2)
  expect_equal(str_length("abc"), 3)
})

...

[jimhester]

@ctberthiaume I sent a PR to the book at https://github.com/hadley/r-pkgs/pull/478

[Christoph999]

I had to create a line with context() in each test. This seems to be a bug. (Version 2.0.0)
Many thanks @jimhester !!!

[Fablepongiste]

Is it not a bug to have context mandatory ?
Should not that not be allowed to have tests without context ?