diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 2adb98d..44f0378 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -75,7 +75,7 @@ public function getConfigTreeBuilder()
             ->end()
             ->validate()
                 ->ifTrue(function ($v) {
-                    if ($v['persistence'] === 'factory') {
+                    if (isset($v['persistence']) && $v['persistence'] === 'factory') {
                         return ! isset($v['collection_factory']['service_id'], $v['collection_factory']['method']);
                     }
 
diff --git a/Tests/DependencyInjection/ConfigurationTest.php b/Tests/DependencyInjection/ConfigurationTest.php
new file mode 100644
index 0000000..68c7f85
--- /dev/null
+++ b/Tests/DependencyInjection/ConfigurationTest.php
@@ -0,0 +1,170 @@
+<?php
+
+/*
+ * This file is part of the qandidate-labs/qandidate-toggle-bundle package.
+ *
+ * (c) Qandidate.com <opensource@qandidate.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Qandidate\Bundle\ToggleBundle\DependencyInjection;
+
+use Matthias\SymfonyConfigTest\PhpUnit\ConfigurationTestCaseTrait;
+use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
+
+class ConfigurationTest extends \PHPUnit_Framework_TestCase
+{
+    use ConfigurationTestCaseTrait;
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getConfiguration()
+    {
+        return new Configuration();
+    }
+
+    /**
+     * @test
+     */
+    public function it_accepts_empty_configuration_and_configures_defaults()
+    {
+        $this->assertProcessedConfigurationEquals(
+            [
+                [],
+            ],
+            [
+                'persistence'     => 'in_memory',
+                'context_factory' => null,
+                'redis_namespace' => 'toggle_%kernel.environment%',
+                'redis_client'    => null,
+                'toggles'         => [],
+            ]
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function it_defaults_to_in_memory_persistence()
+    {
+        $this->assertProcessedConfigurationEquals(
+            [
+                [],
+            ],
+            [
+                'persistence' => 'in_memory',
+            ],
+            'persistence'
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function it_configures_toggles_without_conditions()
+    {
+        $this->assertProcessedConfigurationEquals(
+            [
+                [
+                    'toggles' => [
+                        'always-active-feature' => [
+                            'name'   => 'always-active-feature',
+                            'status' => 'always-active',
+                        ],
+                        'inactive-feature' => [
+                            'name'   => 'inactive-feature',
+                            'status' => 'inactive',
+                        ],
+                    ]
+                ],
+            ],
+            [
+                'toggles' => [
+                    'always_active_feature' => [
+                        'name'       => 'always-active-feature',
+                        'status'     => 'always-active',
+                        'conditions' => [],
+                    ],
+                    'inactive_feature' => [
+                        'name'       => 'inactive-feature',
+                        'status'     => 'inactive',
+                        'conditions' => [],
+                    ],
+                ],
+            ],
+            'toggles'
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function it_configures_toggles_with_conditions()
+    {
+        $this->assertProcessedConfigurationEquals(
+            [
+                [
+                    'toggles' => [
+                        'conditionally-active' => [
+                            'name' => 'conditionally-active',
+                            'status' => 'conditionally-active',
+                            'conditions' => [
+                                [
+                                    'name' => 'operator-condition',
+                                    'key'  => 'user_id',
+                                    'operator' => [
+                                       'name' => 'greater-than',
+                                       'value' => 42,
+                                    ],
+                                ],
+                            ],
+                         ],
+                    ],
+                ],
+            ],
+            [
+                'toggles' => [
+                    'conditionally_active' => [
+                        'name' => 'conditionally-active',
+                        'status' => 'conditionally-active',
+                        'conditions' => [
+                            [
+                                'name' => 'operator-condition',
+                                'key'  => 'user_id',
+                                'operator' => [
+                                    'name' => 'greater-than',
+                                    'value' => 42,
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+            'toggles'
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function it_requires_collection_factory_to_be_set_when_persistence_is_factory()
+    {
+        $this->expectException(InvalidConfigurationException::class);
+        $this->expectExceptionMessage('Invalid configuration for path "qandidate_toggle": When choosing "factory" persistence make sure you set "collection_factory.service_id" and "collection_factory.method"');
+
+        $this->assertProcessedConfigurationEquals(
+            [
+                [
+                    'persistence' => 'factory',
+                ],
+            ],
+            [
+                'persistence' => 'factory',
+            ],
+            'persistence'
+        );
+    }
+}
diff --git a/composer.json b/composer.json
index 57e79f3..d8c9b89 100644
--- a/composer.json
+++ b/composer.json
@@ -31,8 +31,9 @@
         "symfony/browser-kit": "^2.7||^3.0||^4.0",
         "twig/twig": "~1.16,>=1.16.2",
         "symfony/twig-bundle": "^2.7||^3.0||^4.0",
-        "phpunit/phpunit": "^5.0 || ^4.8.10",
-        "matthiasnoback/symfony-dependency-injection-test": "^1.1"
+        "phpunit/phpunit": "^5.2",
+        "matthiasnoback/symfony-dependency-injection-test": "^1.2",
+        "matthiasnoback/symfony-config-test": "^2.2"
     },
     "suggest": {
         "twig/twig": "For using the twig helper"