Implement exception if missing Queue config key. Fixes #102

src/Plugin.php

@@ -50,6 +50,13 @@ class Plugin extends BasePlugin
      */
     public function bootstrap(PluginApplicationInterface $app): void
     {
+        if (!Configure::read('Queue')) {
+            throw new \InvalidArgumentException(
+                'Missing `Queue` configuration key, please check the CakePHP Queue documentation' .
+                ' to complete the plugin setup.'
+            );
+        }
+
         foreach (Configure::read('Queue') as $key => $data) {
             if (QueueManager::getConfig($key) === null) {
                 QueueManager::setConfig($key, $data);

tests/TestCase/PluginTest.php

@@ -0,0 +1,55 @@
+<?php
+declare(strict_types=1);
+
+namespace Cake\Queue\Test\TestCase;
+
+use Cake\Core\Configure;
+use Cake\Queue\Plugin;
+use Cake\Queue\QueueManager;
+use Cake\TestSuite\TestCase;
+use TestApp\Application;
+
+class PluginTest extends TestCase
+{
+    /**
+     * Test Plugin bootstrap with no config
+     *
+     * @return void
+     */
+    public function testBootstrapNoConfig()
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Missing `Queue` configuration key, please check the CakePHP Queue documentation to complete the plugin setup');
+        Configure::delete('Queue');
+        $plugin = new Plugin();
+        $app = $this->getMockBuilder(Application::class)->disableOriginalConstructor()->getMock();
+        $plugin->bootstrap($app);
+    }
+
+    /**
+     * Test Plugin bootstrap with config
+     *
+     * @return void
+     */
+    public function testBootstrapWithConfig()
+    {
+        $queueConfig = [
+            'url' => 'null:',
+            'queue' => 'default',
+            'logger' => 'stdout',
+        ];
+        Configure::write('Queue', ['default' => $queueConfig]);
+        $plugin = new Plugin();
+        $app = $this->getMockBuilder(Application::class)->disableOriginalConstructor()->getMock();
+        $plugin->bootstrap($app);
+        $queueConfig['url'] = [
+            'transport' => 'null:',
+            'client' => [
+                'router_topic' => 'default',
+                'router_queue' => 'default',
+                'default_queue' => 'default',
+            ],
+        ];
+        $this->assertEquals($queueConfig, QueueManager::getConfig('default'));
+    }
+}