add test

tests/Http/RedirectResponseTest.php

@@ -0,0 +1,24 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+use System\Http\RedirectResponse;
+use System\Integrate\Testing\TestResponse;
+
+class RedirectResponseTest extends TestCase
+{
+    /** @test */
+    public function itCanGetResponeContent()
+    {
+        $res      = new RedirectResponse('/login');
+        $redirect = new TestResponse($res);
+
+        $redirect->assertSee('Redirecting to /login');
+        $redirect->assertStatusCode(302);
+
+        foreach ($res->getHeaders() as $key => $value) {
+            if ('Location' === $key) {
+                $this->assertEquals('/login', $value);
+            }
+        }
+    }
+}