Symfony Config Test

By Matthias Noback and contributors

Writing configuration classes using the Symfony Config Component can be quite hard. To help you verify the validity of the resulting config node tree, this library provides a PHPUnit test case and some custom assertions.

Installation

Using Composer:

composer require --dev matthiasnoback/symfony-config-test

Usage

Create a test case and use the trait from Matthias\SymfonyConfigTest\PhpUnit\ConfigurationTestCaseTrait. Then implement getConfiguration():

<?php

use Matthias\SymfonyConfigTest\PhpUnit\ConfigurationTestCaseTrait;
use PHPUnit\Framework\TestCase;
use App\Configuration;

class ConfigurationTest extends TestCase
{
    use ConfigurationTestCaseTrait;

    protected function getConfiguration(): Configuration
    {
        return new Configuration();
    }
}

Test invalid configuration values

Let's assume the Configuration class you want to test looks like this:

<?php

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

class ConfigurationWithRequiredValue implements ConfigurationInterface
{
    public function getConfigTreeBuilder(): TreeBuilder
    {
        $treeBuilder = new TreeBuilder();

        $rootNode = $treeBuilder->root('root');
        $rootNode
            ->isRequired()
            ->children()
                ->scalarNode('required_value')
                    ->isRequired()
                ->end()
            ->end();

        return $treeBuilder;
    }
}

When you provide an empty array as the value for this configuration, you would expect an exception since the required_value node is required. You can assert that a given set of configuration values is invalid using the assertConfigurationIsInvalid() method:

<?php

use Matthias\SymfonyConfigTest\PhpUnit\ConfigurationTestCaseTrait;
use PHPUnit\Framework\TestCase;

class ConfigurationTest extends TestCase
{
    use ConfigurationTestCaseTrait;

    /**
     * @test
     */
    public function values_are_invalid_if_required_value_is_not_provided(): void
    {
        $this->assertConfigurationIsInvalid(
            [
                [] // no values at all
            ],
            'required_value' // (part of) the expected exception message - optional
        );
    }
}

Test processed configuration values

You may also want to verify that after processing an array of configuration values the result will be as expected:

<?php

use Matthias\SymfonyConfigTest\PhpUnit\ConfigurationTestCaseTrait;
use PHPUnit\Framework\TestCase;

class ConfigurationTest extends TestCase
{
    use ConfigurationTestCaseTrait;

    /**
     * @test
     */
    public function processed_value_contains_required_value(): void
    {
        $this->assertProcessedConfigurationEquals([
            ['required_value' => 'first value'],
            ['required_value' => 'last value']
        ], [
            'required_value'=> 'last value'
        ]);
    }
}

Please note: the first argument of each of the assert* methods is an array of arrays. The extra nesting level allows you to test the merge process. See also the section Merging options of the Config Component documentation.

Test a subset of the configuration tree

Using this library it's possible to test just one branch of your configuration tree. Consider the following node tree definition, which contains the branches array_node_1 and array_node_2:

<?php

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

class ConfigurationWithTwoBranches implements ConfigurationInterface
{
    public function getConfigTreeBuilder(): TreeBuilder
    {
        $treeBuilder = new TreeBuilder();

        $rootNode = $treeBuilder->root('root');
        $rootNode
            ->children()
                ->arrayNode('array_node_1')
                    ->isRequired()
                    ->children()
                        ->scalarNode('required_value_1')
                            ->isRequired()
                        ->end()
                    ->end()
                ->end()
                ->arrayNode('array_node_2')
                    ->isRequired()
                    ->children()
                        ->scalarNode('required_value_2')
                            ->isRequired()
                        ->end()
                    ->end()
                ->end()
            ->end();

        return $treeBuilder;
    }
}

If you want to test, for instance, only the array_node_1 branch from the example below, and ignore the array_node_2, provide array_node_1 as the argument for the $breadcrumbPath parameter of the test helper functions, for example:

/**
 * @test
 */
public function processed_configuration_for_array_node_1(): void
{
    $this->assertProcessedConfigurationEquals(
        [
            ['array_node_1' => ['required_value_1' => 'original value']],
            ['array_node_1' => ['required_value_1' => 'final value']]
        ],
        [
            'array_node_1' => [
                'required_value_1' => 'final value'
            ]
        ],
        // the path of the nodes you want to focus on in this test:
        'array_node_1'
    );
}

This would trigger no validation errors for any value in the array_node_2 branch.

Note that the $breadcrumbPath can be even more specific, e.g. "doctrine.orm" (which would skip configuration processing for branch "doctrine.dbal", etc.).

Also note that you can only traverse over array nodes using the . in the breadcrumb path. The last part of the breadcrumb path can be any other type of node.

Test a subset of the prototyped configuration tree

You can traverse through prototype array nodes using * as its name in the breadcrumb path.

<?php

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

class PrototypedConfiguration implements ConfigurationInterface
{
    public function getConfigTreeBuilder(): TreeBuilder
    {
        $treeBuilder = new TreeBuilder();

        $rootNode = $treeBuilder->root('root');
        $rootNode
            ->children()
                ->arrayNode('array_node')
                    ->useAttributeAsKey('name')
                    ->prototype('array')
                        ->children()
                            ->scalarNode('default_value')->cannotBeEmpty()->defaultValue('foobar')->end()
                            ->scalarNode('required_value')->isRequired()->end()
                        ->end()
                    ->end()
                ->end()
            ->end();

        return $treeBuilder;
    }
}

If you want to test whether default_value is set to foobar by default, but don't want the test to be affected by requirements on required_value node, you can define its path as array_node.*.default_value, for example:

/**
 * @test
 */
public function processed_configuration_for_array_node_1(): void
{
    $this->assertProcessedConfigurationEquals(
        [
            ['array_node' => ['prototype_name' => null]],
        ],
        [
            'array_node' => [
                'prototype_name' => [
                    'default_value' => 'foobar'
                ]
            ]
        ],
        // the path of the nodes you want to focus on in this test:
        'array_node.*.default_value'
    );
}

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