getTestBuilder example

use PHPUnit\Framework\TestCase;
use Symfony\Component\Config\Definition\Builder\ExprBuilder;
use Symfony\Component\Config\Definition\Builder\NodeDefinition;
use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;

class ExprBuilderTest extends TestCase
{
    public function testAlwaysExpression()
    {
        $test = $this->getTestBuilder()
            ->always($this->returnClosure('new_value'))
        ->end();

        $this->assertFinalizedValueIs('new_value', $test);
    }

    public function testIfTrueExpression()
    {
        $test = $this->getTestBuilder()
            ->ifTrue()
            ->then($this->returnClosure('new_value'))