R tryCatch with expectation of testthat

Question

I have the following function:

fun = function(expr) {
  mc = match.call()

  env = as.environment(within(
    list(),
    expr = eval(mc$expr)
  ))

  return(env)
}

which is called internally tryCatch(), so that any error conditions in are exprhandled gracefully.

It works fine with the standard error condition:

tryCatch({
  fun({
    stop('error')
  })
}, error = function(e) {
  message('error happened')
})

# error happened

However, it does not display wait errors testthat(which is preferable for my particular use case):

library(testthat)

tryCatch({
  fun({
    expect_true(FALSE)
  })
}, error = function(e) {
  message('expectation not met')
})

# Error: FALSE isn't true.

or more simply:

library(testthat)

tryCatch({
  expect_true(FALSE)
}, error = function(e) {
  message('expectation not met')
})

# Error: FALSE isn't true.

The wait error is not caught.

This problem arose after the upgrade from R 3.2.2 to R 3.3.0 - that is, wait errors were caught only smoothly in R 3.2.2.

Is there a way to make expectations testthatexpected tryCatch()in R 3.3.0?

Answer 1

expect(), ( ) ,

> debug(expect)
> xx = expect_true(FALSE)
...
Browse[2]> n
debug: exp <- as.expectation(exp, ..., srcref = srcref)
Browse[2]>
...
Browse[2]> class(exp)
[1] "expectation_failure" "expectation"         "condition"   
Browse[2]> Q
> undebug(expect)       

""

> tryCatch(expect_true(FALSE), expectation_failure=conditionMessage)
[1] "FALSE isn't true.\n"

expectation.

, .

result <- withCallingHandlers({
    expect_true(FALSE)
    expect_true(!TRUE)
    expect_true("this sentence")
}, expectation_failure=function(e) {
    cat(conditionMessage(e))
    invokeRestart("continue_test")
})

FALSE isn't true.
!TRUE isn't true.
"this sentence" isn't true.
> result
[1] FALSE

> tryCatch(expect_true(TRUE), expectation_success=class)
[1] "expectation_success" "expectation"         "condition"