Usage of setUseErrorHandler produces Undefined variable error.

[neomerx]

Q	A
PHPUnit version	6.3.0
PHP version	7.1.9
Installation Method	Composer

Test

    public function testErrors()
    {
        $this->setUseErrorHandler(false);

        $this->assertTrue(true);
    }

Produces error

Argument #1 (No Value) of PHPUnit\Framework\TestResult::convertErrorsToExceptions() must be a boolean
PHP Notice:  Undefined variable: oldErrorHandlerSetting in /.../vendor/phpunit/phpunit/src/Framework/TestCase.php on line 887
PHP Stack trace:
PHP   1. {main}() /.../vendor/phpunit/phpunit/phpunit:0
PHP   2. PHPUnit\TextUI\Command::main() /.../vendor/phpunit/phpunit/phpunit:53
PHP   3. PHPUnit\TextUI\Command->run() /.../vendor/phpunit/phpunit/src/TextUI/Command.php:141
PHP   4. PHPUnit\TextUI\TestRunner->doRun() /.../vendor/phpunit/phpunit/src/TextUI/Command.php:212
PHP   5. PHPUnit\Framework\TestSuite->run() /.../vendor/phpunit/phpunit/src/TextUI/TestRunner.php:537
PHP   6. Limoncello\Tests\Application\Packages\Application\ApplicationTest->run() /.../vendor/phpunit/phpunit/src/Framework/TestSuite.php:744