diff --git a/core/tests/Drupal/Tests/Core/Http/HandlerStackConfiguratorTest.php b/core/tests/Drupal/Tests/Core/Http/HandlerStackConfiguratorTest.php
new file mode 100644
index 0000000..2f91eae
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Http/HandlerStackConfiguratorTest.php
@@ -0,0 +1,77 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Http\HandlerStackConfiguratorTest.
+ */
+
+namespace Drupal\Tests\Core\Http;
+
+use Drupal\Core\Http\HandlerStackConfigurator;
+use Drupal\Tests\UnitTestCase;
+use GuzzleHttp\Handler\CurlHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Psr7\Response;
+use Psr\Http\Message\RequestInterface;
+use Symfony\Component\DependencyInjection\Container;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Http\HandlerStackConfigurator
+ * @group http
+ */
+class HandlerStackConfiguratorTest extends UnitTestCase {
+
+  /**
+   * @covers ::configure
+   * @covers ::initializeMiddlewares
+   *
+   * @expectedException \InvalidArgumentException
+   */
+  public function testConfigureWithNonCallableService() {
+    $handler_stack = new HandlerStack();
+
+    $container = new Container();
+    $container->set('test_middleware_non_callable', new TestMiddlewareNonCallable());
+    $middleware_ids = ['test_middleware_non_callable'];
+    $handler_stack_configurator = new HandlerStackConfigurator($container, $middleware_ids);
+    $handler_stack_configurator->configure($handler_stack);
+  }
+
+  /**
+   * @covers ::configure
+   * @covers ::initializeMiddlewares
+   */
+  public function testConfigureWithCallableService() {
+    $handler_stack = new HandlerStack(new CurlHandler());
+
+    $container = new Container();
+    $container->set('test_middleware_callable', new TestMiddlewareCallable());
+    $middleware_ids = ['test_middleware_callable'];
+    $handler_stack_configurator = new HandlerStackConfigurator($container, $middleware_ids);
+    $handler_stack_configurator->configure($handler_stack);
+
+    $request = new Request('GET', '/example');
+    $options = [];
+    /** @var \Psr\Http\Message\ResponseInterface $response */
+    $response = $handler_stack($request, $options);
+    $this->assertEquals(418, $response->getStatusCode());
+  }
+
+}
+
+class TestMiddlewareNonCallable {
+
+}
+
+class TestMiddlewareCallable {
+
+  public function __invoke() {
+    return function ($handler) {
+      return function (RequestInterface $request, array $options) use ($handler) {
+        return new Response(418);
+      };
+    };
+  }
+
+}