Test swallows output buffer when run in a separate process

[decadent]

<?php

class A extends \PHPUnit_Framework_TestCase {

    public function testOne() {
        print '1';
        file_put_contents('aaa1', ob_get_level());
    }

    /**
     * @runInSeparateProcess
     */
    public function testTwo() {
        print '2';
        file_put_contents('aaa2', ob_get_level());
    }

}

$ phpunit -v a.php
PHPUnit 3.7.31 by Sebastian Bergmann.

.1.

Time: 155 ms, Memory: 33.75Mb

OK (2 tests, 0 assertions)
$ cat aaa1
1
$ cat aaa2
2

[decadent]

I know that both output buffering and running tests in separate processes were sources of annoying issues for phpunit, and both are not regular use cases, so consider this a low priority issue or something.
Only I suppose that the behavior should be consistent whether running in one process or in separate processes. So maybe the separate-process case should execute a course completely independent of the same-process case in order to not inherit any state and not cause any more trouble at all?

[donquixote]

I use process isolation a lot. It is important for testing stuff like a class loader.
And now I can't figure out how to print anything while "@runTestsInSeparateProcesses" and "@preserveGlobalState disabled" are on. It would be great to see this fixed.

[decadent]

@donquixote You can actually open php://stdout directly and write to it. The stuff printed will cause an error in deserialization of the test results and will be output as an Exception.

I guess this indicates that what's missing is transmission of the output from the test in the serialized data.

[sun]

I can confirm that the output is not re-printed to STDOUT.

what's missing is transmission of the output from the test in the serialized data

The process isolation script template TestCaseMethod.tpl.dist does capture the output already:

    ob_start();
    $test->run($result);
    $output = ob_get_clean();
    print serialize(
      array(
        'testResult'    => $test->getResult(),
        'numAssertions' => $test->getNumAssertions(),
        'result'        => $result,
        'output'        => $output
      )
    );

If I get you right, then you'd like the subprocess output to get forwarded to STDOUT of the parent/main process?

PHPUnit_Util_PHP::processChildResult() immediately forwards STDERR already:

        if (!empty($stderr)) {
            $result->addError(
              $test,
              new PHPUnit_Framework_Exception(trim($stderr)), $time
            );

It seemingly forwards STDOUT, too:

            if ($childResult !== false) {
                if (!empty($childResult['output'])) {
                    print $childResult['output'];
                }

The $stdout variable itself is not consumed, and actually replaced with unserialize($stdout):

                if (strpos($stdout, "#!/usr/bin/env php\n") === 0) {
                    $stdout = substr($stdout, 19);
                }
                $childResult = unserialize(str_replace("#!/usr/bin/env php\n", '', $stdout));

So theoretically, output of the child process should be forwarded to the parent process already. Perhaps there's a bug in this code though. Can you debug?

Alternatively, the execution of tests running in isolation may be wrapped into another output buffer somewhere else.

[whatthejeff]

This should be fixed in the next stable release. Thanks!

[sun]

@whatthejeff Awesome! Question:

Is a technical analysis like mine above helpful? Or useless noise?

I'm just starting to dive deep, so I don't consider myself to be in a position to fix issues like this directly (just yet), but thought it might be helpful to share insights gathered while debugging other stuff ;)

Just curious whether comments like the above are a waste of everyone's time :)

[whatthejeff]

@sun It's actually very helpful and very much appreciated!

[Flimm]

What version was this released in?

To answer my own question, it was released in v4.1.5.

$ git describe --contains 8337d8f93fc451252455120a8e0bd0cc7d5659cf
4.1.5~9

Which is odd, because I am running v4.7.6, and I am still experiencing this issue of PHPUnit swallowing output when run in separate processes.

[DavidSoussan]

I am experiencing the same issue: PHPUnit swallowing output when run in separate processes. using version 5.6.3