Created middleware which closes DB connection after every request

module/Common/test/Middleware/CloseDbConnectionMiddlewareTest.php

@@ -0,0 +1,53 @@
+<?php
+declare(strict_types=1);
+
+namespace ShlinkioTest\Shlink\Common\Middleware;
+
+use Doctrine\DBAL\Connection;
+use Doctrine\ORM\EntityManagerInterface;
+use PHPUnit\Framework\TestCase;
+use Prophecy\Prophecy\ObjectProphecy;
+use Psr\Http\Server\RequestHandlerInterface;
+use Shlinkio\Shlink\Common\Middleware\CloseDbConnectionMiddleware;
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+
+class CloseDbConnectionMiddlewareTest extends TestCase
+{
+    /** @var CloseDbConnectionMiddleware */
+    private $middleware;
+    /** @var ObjectProphecy */
+    private $handler;
+    /** @var ObjectProphecy */
+    private $em;
+
+    public function setUp()
+    {
+        $this->handler = $this->prophesize(RequestHandlerInterface::class);
+        $this->em = $this->prophesize(EntityManagerInterface::class);
+
+        $this->middleware = new CloseDbConnectionMiddleware($this->em->reveal());
+    }
+
+    /**
+     * @test
+     */
+    public function connectionIsClosedWhenMiddlewareIsProcessed()
+    {
+        $req = ServerRequestFactory::fromGlobals();
+        $resp = new Response();
+
+        $conn = $this->prophesize(Connection::class);
+        $closeConn = $conn->close()->will(function () {
+        });
+        $getConn = $this->em->getConnection()->willReturn($conn->reveal());
+        $handle = $this->handler->handle($req)->willReturn($resp);
+
+        $result = $this->middleware->process($req, $this->handler->reveal());
+
+        $this->assertSame($result, $resp);
+        $getConn->shouldHaveBeenCalledOnce();
+        $closeConn->shouldHaveBeenCalledOnce();
+        $handle->shouldHaveBeenCalledOnce();
+    }
+}