Test suite fails on warning

[garak]

Q	A
PHPUnit version	8.0.3
PHP version	7.2.15
Installation Method	Composer

Test suite is failing when there are warnings, e.g. running echo $? after tests is returning 1 instead of 0.

I also tried to explicit failOnWarning option to false (it should be the default), no luck.

Output of composer info | sort:

doctrine/instantiator              1.1.0   A small, lightweight utility to instantiate objects in PHP without invoking their constructors
ircmaxell/security-lib             v1.1.0  A Base Security Library
myclabs/deep-copy                  1.8.1   Create deep copies (clones) of your objects
paragonie/random_compat            v2.0.18 PHP 5.x polyfill for random_bytes() and random_int() from PHP 7
paragonie/random-lib               v2.0.0  A Library For Generating Secure Random Numbers
paragonie/sodium_compat            v1.8.1  Pure PHP implementation of libsodium; uses the PHP extension if it exists
phar-io/manifest                   1.0.3   Component for reading phar.io manifest information from a PHP Archive (PHAR)
phar-io/version                    2.0.1   Library for handling version information and constraints
phpdocumentor/reflection-common    1.0.1   Common reflection classes used by phpdocumentor to reflect the code structure
phpdocumentor/reflection-docblock  4.3.0   With this component, a library can provide support for annotations via DocBlocks or otherwise retrieve info...
phpdocumentor/type-resolver        0.4.0  
phpspec/prophecy                   1.8.0   Highly opinionated mocking framework for PHP 5.3+
phpunit/php-code-coverage          7.0.2   Library that provides collection, processing, and rendering functionality for PHP code coverage information.
phpunit/php-file-iterator          2.0.2   FilterIterator implementation that filters files based on a list of suffixes.
phpunit/php-text-template          1.2.1   Simple template engine.
phpunit/php-timer                  2.0.0   Utility class for timing
phpunit/php-token-stream           3.0.1   Wrapper around PHP's tokenizer extension.
phpunit/phpunit                    8.0.3   The PHP Unit Testing framework.
sebastian/code-unit-reverse-lookup 1.0.1   Looks up which function or method a line of code belongs to
sebastian/comparator               3.0.2   Provides the functionality to compare PHP values for equality
sebastian/diff                     3.0.2   Diff implementation
sebastian/environment              4.1.0   Provides functionality to handle HHVM/PHP environments
sebastian/exporter                 3.1.0   Provides the functionality to export PHP variables for visualization
sebastian/global-state             3.0.0   Snapshotting of global state
sebastian/object-enumerator        3.0.3   Traverses array structures and object graphs to enumerate all referenced objects
sebastian/object-reflector         1.1.1   Allows reflection of object attributes, including inherited and non-public ones
sebastian/recursion-context        3.0.0   Provides functionality to recursively process PHP variables
sebastian/resource-operations      2.0.1   Provides a list of PHP built-in functions that operate on resources
sebastian/version                  2.0.1   Library that helps with managing the version number of Git-hosted PHP projects
symfony/polyfill-ctype             v1.10.0 Symfony polyfill for ctype functions
symfony/polyfill-mbstring          v1.10.0 Symfony polyfill for the Mbstring extension
theseer/tokenizer                  1.1.0   A small library for converting tokenized PHP source code into XML and potentially other formats
webmozart/assert                   1.4.0   Assertions to validate method input/output with nice error messages.