using vector class argument in expect_is causes errors in test_dir

[goldingn]

TL;DR: When calling test_dir on a test containing an expect_is call with character vector class argument, two errors are reported, causing an error in a vapply call before ever reporting the failures.

expect_is mangles the error message slightly when the class argument is a vector:

x <- NA
class(x) <- c('a')
expect_is(x, c('b', 'c'))

Error: x inherits from a not bx inherits from a not c

which isn't so bad, but when used in test_dir (and quite possibly others) it leads to the following cryptic error:

dir <- tempdir()
write("test_that('blah',{
         x <- NA
         class(x) <- c('a')
         expect_is(x, c('b', 'c'))
       })",
      file = paste0(dir, '/test-demo.R'))
test_dir(dir)

Error in vapply(seq_len(n), function(i) { : values must be length 1, but FUN(X[[1]]) result is length 2

The error is thrown by the following line in test_dir:

current_reporter$end_reporter()

because failure_summary returns a vector of length two mangling the vapply call

[1] "1. Failure (at test-demo.R#4): blah -----------------------------------------\nx inherits from a not b"
[2] "1. Failure (at test-demo.R#4): blah -----------------------------------------\nx inherits from a not c"

Hope this is helpful!

[goldingn]

👍