How to inspect a variable when testing with `drush test-run`.

Question

When testing with my SimpleTests, I want to inspect a variable. var_dump() and the likes are not being rendered in the output of Drush, Xdebug interactive debugger does not work due to the simulated browser being ran in DrupalWebTest.

How can I render, export, inspect or otherwise dump the contents of a variable in my code? I.e. the DrupalWebTest of dpm(), var_export() and such.

Answer 1

The documentation for Troubleshooting Tests has a number of insights:

1. Use debug() in Drupal 7. This will work during testing, and display the output right in your test results.
2. Print them with a test that always passes (using something like $this->pass(var_export($var, TRUE));). It's a bit of a kludge, but it'll work in the absence of anything else.

Answer 2

Call DrupalTestCase::assert() passing the message to show.

$this->assert(TRUE,
  t('Variable content: @variable', array('@variable' => var_export($variable, TRUE))
);

This is similar to the code used by DrupalTestCase::assertIdentical(). The difference is that in your case the first argument is TRUE because you are just outputting the content of a variable, which never fails.

protected function assertIdentical($first, $second, $message = '', $group = 'Other') {
  return $this->assert($first === $second, $message ? $message : t('Value @first is identical to value @second.', array('@first' => var_export($first, TRUE), '@second' => var_export($second, TRUE))), $group);
}

Answer 3

Have you tried print_r($variable)? For a human friendly output you could try

print '<pre>';
print_r($variable);
print '</pre>';

Answer 4

I can suggest 2 solutions

1) you can use watchdog.

watchdog($type, $message); Just put your variables with custom type name like:

watchdog('drush_test_run', print_r($message));

2) you can create some file log.txt and write variables into it with php file functions.

Answer 5

Any of these answers would be OK under most circumstances except that the problem I was having with a specific test case was do to the fact that I implemented an exec call and that function captures all output.

In my case I replaced the exec call with passthru and that fixed the issue for me.