Functional test to ensure no issue with plugins in sync nor async requests

.travis.yml

@@ -32,6 +32,8 @@ jobs:
     env: DEPENDENCIES="dunglas/symfony-lock:^3"
   - php: 7.2
     env: DEPENDENCIES="dunglas/symfony-lock:^4"
+  - php: 7.2
+    env: TEST_COMMAND="./vendor/bin/phpunit" DEPENDENCIES="phpunit/phpunit:^7.5 nyholm/psr7:^1.0"
 
     # Latest dev release
   - php: 7.3

phpunit.xml.dist

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit bootstrap="./vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true">
+
+    <testsuites>
+        <testsuite name="HTTPlug unit tests">
+            <directory suffix="Test.php">./tests</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>

tests/PluginClientTest.php

@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace tests\Http\Client\Common;
+
+use Http\Client\Common\Plugin;
+use Http\Client\Common\Plugin\HeaderAppendPlugin;
+use Http\Client\Common\Plugin\RedirectPlugin;
+use Http\Client\Common\PluginClient;
+use Http\Client\HttpAsyncClient;
+use Http\Client\Promise\HttpFulfilledPromise;
+use Http\Promise\Promise;
+use Nyholm\Psr7\Request;
+use Nyholm\Psr7\Response;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Client\ClientInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class PluginClientTest extends TestCase
+{
+    /**
+     * @dataProvider clientAndMethodProvider
+     */
+    public function testRestartChain(PluginClient $client, string $method, string $returnType)
+    {
+        $request = new Request('GET', 'https://example.com');
+        $result = call_user_func([$client, $method], $request);
+
+        $this->assertInstanceOf($returnType, $result);
+    }
+
+    public function clientAndMethodProvider()
+    {
+        $syncClient = new class() implements ClientInterface {
+            public function sendRequest(RequestInterface $request): ResponseInterface
+            {
+                return new Response();
+            }
+        };
+
+        $asyncClient = new class() implements HttpAsyncClient {
+            public function sendAsyncRequest(RequestInterface $request)
+            {
+                return new HttpFulfilledPromise(new Response());
+            }
+        };
+
+        $headerAppendPlugin = new HeaderAppendPlugin(['Content-Type' => 'text/html']);
+        $redirectPlugin = new RedirectPlugin();
+        $restartOncePlugin = new class() implements Plugin {
+            private $firstRun = true;
+
+            public function handleRequest(RequestInterface $request, callable $next, callable $first): Promise
+            {
+                if ($this->firstRun) {
+                    $this->firstRun = false;
+
+                    return $first($request);
+                }
+                $this->firstRun = true;
+
+                return $next($request);
+            }
+        };
+
+        $plugins = [$headerAppendPlugin, $restartOncePlugin, $redirectPlugin];
+
+        $pluginClient = new PluginClient($syncClient, $plugins);
+        yield [$pluginClient, 'sendRequest', ResponseInterface::class];
+        yield [$pluginClient, 'sendAsyncRequest', Promise::class];
+
+        // Async
+        $pluginClient = new PluginClient($asyncClient, $plugins);
+        yield [$pluginClient, 'sendRequest', ResponseInterface::class];
+        yield [$pluginClient, 'sendAsyncRequest', Promise::class];
+    }
+}