Allow API responses to be mocked in tests

modules/apigee_edge_debug/src/SDKConnector.php

@@ -23,6 +23,7 @@
 use Apigee\Edge\ClientInterface;
 use Drupal\apigee_edge\SDKConnector as OriginalSDKConnector;
 use Drupal\apigee_edge\SDKConnectorInterface;
+use Drupal\Component\Utility\NestedArray;
 use Drupal\key\KeyInterface;
 use Http\Message\Authentication;
 
@@ -92,7 +93,7 @@ public function getClient(?Authentication $authentication = NULL, ?string $endpo
       return $this->defaultClient;
     }
 
-    return $this->innerService->getClient($authentication, $endpoint, array_merge($options, $extra_options));
+    return $this->innerService->getClient($authentication, $endpoint, NestedArray::mergeDeep($options, $extra_options));
   }
 
   /**

tests/modules/apigee_edge_test/apigee_edge_test.services.yml

@@ -27,6 +27,18 @@ services:
       # Without this property for decorated services, serialization will fail. @see: https://www.drupal.org/project/drupal/issues/2536370
       _serviceId: apigee_edge.sdk_connector
 
+  apigee_edge_test.http_middleware.mock_api_request:
+    class: Drupal\apigee_edge_test\HttpClientMiddleware\MockApiRequestEventDispatcher
+    arguments: ['@event_dispatcher']
+    tags:
+      - { name: http_client_middleware }
+
+  apigee_edge_test.mock_api_request_subscriber.api_response_from_state:
+    class: Drupal\apigee_edge_test\EventSubscriber\MockApiRequestSubscriber\ApiResponseFromState
+    arguments: ['@state', '@settings']
+    tags:
+      - { name: event_subscriber }
+
   apigee_edge_test.converter.user_developer:
     class: Drupal\apigee_edge_test\UserDeveloperConverter
     decorates: apigee_edge.converter.user_developer

tests/modules/apigee_edge_test/src/Event/ApiRequestEvent.php

@@ -0,0 +1,102 @@
+<?php
+
+/**
+ * Copyright 2018 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+namespace Drupal\apigee_edge_test\Event;
+
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * A mock-able API request event to the Apigee backend.
+ *
+ * An event subscriber (mock API request subscriber) can decide whether it
+ * reacts to an API request or not. Every API request subscriber gets called for
+ * an API request - unless stopPropagation() method had been called on an event
+ * by a subscriber which aborts the execution of further subscribers - multiple
+ * subscriber can perform an action for a request but only one mock API response
+ * gets return to an API request.
+ *
+ * @see \Drupal\apigee_edge_test\HttpClientMiddleware\MockApiRequestEventDispatcher
+ */
+final class ApiRequestEvent extends Event {
+
+  /**
+   * The event name.
+   *
+   * @var string
+   */
+  public const EVENT_NAME = 'apigee_edge_test.mock_http_request_event';
+
+  /**
+   * A mock API response if any.
+   *
+   * @var \Psr\Http\Message\ResponseInterface|null
+   */
+  protected $response;
+
+  /**
+   * The API request.
+   *
+   * @var \Psr\Http\Message\RequestInterface
+   */
+  private $request;
+
+  /**
+   * ApiRequestEvent constructor.
+   *
+   * @param \Psr\Http\Message\RequestInterface $request
+   *   The API request.
+   */
+  public function __construct(RequestInterface $request) {
+    $this->request = $request;
+  }
+
+  /**
+   * The API request.
+   *
+   * @return \Psr\Http\Message\RequestInterface
+   *   The API request.
+   */
+  public function getRequest(): RequestInterface {
+    return $this->request;
+  }
+
+  /**
+   * The mock API response, if any.
+   *
+   * @return \Psr\Http\Message\ResponseInterface|null
+   *   The mock API response for the request or null.
+   */
+  public function getResponse(): ?ResponseInterface {
+    return $this->response;
+  }
+
+  /**
+   * The mock API response for a request.
+   *
+   * @param \Psr\Http\Message\ResponseInterface|null $response
+   *   The mock API response or null if there is no response.
+   */
+  public function setResponse(?ResponseInterface $response): void {
+    $this->response = $response;
+  }
+
+}

tests/modules/apigee_edge_test/src/EventSubscriber/MockApiRequestSubscriber/ApiResponseFromState.php

@@ -0,0 +1,165 @@
+<?php
+
+/**
+ * Copyright 2018 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+namespace Drupal\apigee_edge_test\EventSubscriber\MockApiRequestSubscriber;
+
+use Drupal\apigee_edge_test\Event\ApiRequestEvent;
+use Drupal\Core\Site\Settings;
+use Drupal\Core\State\State;
+use GuzzleHttp\Psr7;
+use Psr\Http\Message\ResponseInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Returns mock API responses from the Drupal State key-value store.
+ *
+ * It uses the State as a FIFO storage.
+ */
+final class ApiResponseFromState implements EventSubscriberInterface {
+
+  /**
+   * The settings that controls whether mocked requests get captured or not.
+   *
+   * @var string
+   */
+  public const SETTINGS_CAPTURE_REQUESTS = 'apigee_edge_test_state_response_provider_capture_requests';
+
+  /**
+   * The key that this provider uses as storage for mock responses.
+   *
+   * @var string
+   */
+  private const STATE_KEY_RESPONSE_STORAGE = 'apigee_edge_test.mock_response_provider.state.response_storage';
+
+  /**
+   * The key that this provider uses as storage to captured mocked requests.
+   *
+   * @var string
+   */
+  private const STATE_KEY_REQUEST_STORAGE = 'apigee_edge_test.mock_response_provider.state.request_storage';
+
+  /**
+   * The state backend.
+   *
+   * @var \Drupal\Core\State\StateInterface
+   */
+  private $state;
+
+  /**
+   * Settings.
+   *
+   * @var \Drupal\Core\Site\Settings
+   */
+  private $settings;
+
+  /**
+   * ApiResponseFromState constructor.
+   *
+   * @param \Drupal\Core\State\State $state
+   *   The state backend.
+   * @param \Drupal\Core\Site\Settings $settings
+   *   Settings.
+   */
+  public function __construct(State $state, Settings $settings) {
+    $this->state = $state;
+    $this->settings = $settings;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents(): array {
+    return [
+      ApiRequestEvent::EVENT_NAME => 'handle',
+    ];
+  }
+
+  /**
+   * Returns a mock API response from the state storage if it is not empty.
+   *
+   * @param \Drupal\apigee_edge_test\Event\ApiRequestEvent $event
+   *   The API request event.
+   */
+  public function handle(ApiRequestEvent $event): void {
+    $queued_responses = $this->getQueuedResponses();
+    if (!empty($queued_responses)) {
+      /** @var \Psr\Http\Message\ResponseInterface $response */
+      $response = array_shift($queued_responses);
+      $response = Psr7\parse_response($response);
+      $event->setResponse($response);
+      $this->state->set(static::STATE_KEY_RESPONSE_STORAGE, $queued_responses);
+      if ($this->settings->get(static::SETTINGS_CAPTURE_REQUESTS, FALSE)) {
+        $request_storage = $this->state->get(static::STATE_KEY_REQUEST_STORAGE, []);
+        $request_storage[] = Psr7\str($event->getRequest());
+        $this->state->set(static::STATE_KEY_REQUEST_STORAGE, $request_storage);
+      }
+      // Do not call other providers because either a request-independent API
+      // response is available in the storage or there should not be any
+      // response in the storage.
+      $event->stopPropagation();
+    }
+  }
+
+  /**
+   * Adds an API response to the queue.
+   *
+   * @param \Psr\Http\Message\ResponseInterface $response
+   *   A mock API response.
+   */
+  public function queueResponse(ResponseInterface $response): void {
+    // We must clear the static cache here because items can stack in there in
+    // tests.
+    $this->state->resetCache();
+    $queued_responses = $this->state->get(static::STATE_KEY_RESPONSE_STORAGE, []);
+    $queued_responses[] = Psr7\str($response);
+    $this->state->set(static::STATE_KEY_RESPONSE_STORAGE, $queued_responses);
+  }
+
+  /**
+   * Returns queued API responses.
+   *
+   * @return \Psr\Http\Message\ResponseInterface[]
+   *   Mock API responses in the queue.
+   */
+  public function getQueuedResponses(): array {
+    return $this->state->get(static::STATE_KEY_RESPONSE_STORAGE, []);
+  }
+
+  /**
+   * Clears queued mock API responses and captured mocked API requests.
+   */
+  public function clear(): void {
+    $this->state->delete(static::STATE_KEY_RESPONSE_STORAGE);
+    $this->state->delete(static::STATE_KEY_REQUEST_STORAGE);
+  }
+
+  /**
+   * Returns mocked API requests that got mocked if capturing was enabled.
+   *
+   * @return \Psr\Http\Message\RequestInterface[]
+   *   Captured API requests that got mocked.
+   */
+  public function getMockedRequests(): array {
+    return array_map(static function (string $item) {
+      return Psr7\parse_request($item);
+    }, $this->state->get(static::STATE_KEY_REQUEST_STORAGE, []));
+  }
+
+}

tests/modules/apigee_edge_test/src/HttpClientMiddleware/MockApiRequestEventDispatcher.php

@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * Copyright 2018 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+namespace Drupal\apigee_edge_test\HttpClientMiddleware;
+
+use Drupal\apigee_edge_test\Event\ApiRequestEvent;
+use Drupal\apigee_edge_test\SDKConnector;
+use GuzzleHttp\Promise\FulfilledPromise;
+use Psr\Http\Message\RequestInterface;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
+
+/**
+ * Allows to mock Apigee API requests.
+ */
+final class MockApiRequestEventDispatcher {
+
+  /**
+   * The event dispatcher.
+   *
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
+   */
+  private $eventDispatcher;
+
+  /**
+   * MockApiRequestEventDispatcher constructor.
+   *
+   * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
+   *   The event dispatcher.
+   */
+  public function __construct(EventDispatcherInterface $event_dispatcher) {
+    $this->eventDispatcher = $event_dispatcher;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __invoke() {
+    return function (callable $handler) {
+      return function (RequestInterface $request, array $options) use ($handler) {
+        if ($request->hasHeader(SDKConnector::HEADER)) {
+          $event = new ApiRequestEvent($request);
+          $this->eventDispatcher->dispatch(ApiRequestEvent::EVENT_NAME, $event);
+
+          if ($event->getResponse()) {
+            return new FulfilledPromise($event->getResponse());
+          }
+        }
+
+        // No mock API subscriber provided a mock response for this HTTP
+        // request. Let's call the real API backend.
+        return $handler($request, $options);
+      };
+    };
+  }
+
+}