assert mistakenly outputs $status and $output

[ztombol]

Issue

assert tests an expression and outputs data that, confusingly, may not be related to it. This helper doesn't actually use run to capture $status and $output when it tests the expression, but displays the values set during the most recent invocation of run.

When $status and/or $output is important, run and the appropriate assertion should be used instead.

_Note:_ I'm already working on a fix that should be upstream soon. I opened the issue just to document the bug.

Example

Tests:

#!/usr/bin/env bats

load test_helper

test_fn () {
  echo 'Success!'
}

@test 'assert bug: confusing output and status' {
  run test_fn
  assert [ 1 = 3 ]
}

@test 'assert bug: empty output and status' {
  test_fn
  assert [ 1 = 3 ]
}

Output:

 ✗ assert bug: confusing output and status
   (from function `assert' in file ./test_helper/bats-assert/src/assert.bash, line 82,
    in test file ./01-test.bats, line 11)
     `assert [ 1 = 3 ]' failed

   -- assertion failed --
   expression : [ 1 = 3 ]
   status     : 0
   output     : Success!
   --

 ✗ assert bug: empty output and status
   (from function `assert' in file ./test_helper/bats-assert/src/assert.bash, line 82,
    in test file ./01-test.bats, line 16)
     `assert [ 1 = 3 ]' failed
   Success!

   -- assertion failed --
   expression : [ 1 = 3 ]
   status     : 
   output     : 
   --