diff --git a/tests/src/Unit/RouteNormalizerRequestSubscriberTest.php b/tests/src/Unit/RouteNormalizerRequestSubscriberTest.php
new file mode 100644
index 0000000..cfa9935
--- /dev/null
+++ b/tests/src/Unit/RouteNormalizerRequestSubscriberTest.php
@@ -0,0 +1,225 @@
+<?php
+
+namespace Drupal\Tests\redirect\Unit\EventSubscriber;
+
+use Drupal\Tests\UnitTestCase;
+use Drupal\redirect\EventSubscriber\RouteNormalizerRequestSubscriber;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+
+/**
+ * Tests the route normalizer.
+ * 
+ * @group redirect
+ * 
+ * @coversDefaultClass \Drupal\redirect\EventSubscriber\RouteNormalizerRequestSubscriber
+ */
+class RouteNormalizerRequestSubscriberTest extends UnitTestCase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $kill_switch = $this->getMock('\Drupal\Core\PageCache\ResponsePolicy\KillSwitch');
+    $kill_switch->expects($this->any())
+      ->method('trigger')
+      ->withAnyParameters()
+      ->will($this->returnValue(NULL));
+    $container = new ContainerBuilder();
+    $container->set('page_cache_kill_switch', $kill_switch);
+    \Drupal::setContainer($container);
+  }
+
+  /**
+   * @covers ::onKernelRequestRedirect
+   */
+  public function testSkipIfFlagNotEnabled() {
+    $request_uri = 'https://example.com/route-to-normalize';
+    $request_query = [];
+
+    $event = $this->getGetResponseEventStub($request_uri, http_build_query($request_query));
+    // We set 'route_normalizer_enabled' config to FALSE and expect to leave onKernelRequestRedirect at the beginning,
+    // i.e. $this->redirectChecker->canRedirect($request) should never be called.
+    $subscriber = $this->getSubscriber($request_uri, FALSE, FALSE);
+    $subscriber->onKernelRequestRedirect($event);
+  }
+
+  /**
+   * @covers ::onKernelRequestRedirect
+   */
+  public function testSkipIfSubRequest() {
+    $request_uri = 'https://example.com/route-to-normalize';
+    $request_query = [];
+
+    $event = $this->getGetResponseEventStub($request_uri, http_build_query($request_query), HttpKernelInterface::SUB_REQUEST);
+    // We are using SUB_REQUEST as the request type and expect to leave onKernelRequestRedirect at the beginning,
+    // i.e. $this->redirectChecker->canRedirect($request) should never be called.
+    $subscriber = $this->getSubscriber($request_uri, TRUE, FALSE);
+    $subscriber->onKernelRequestRedirect($event);
+  }
+
+  /**
+   * @covers ::onKernelRequestRedirect
+   */
+  public function testSkipIfRequestAttribute() {
+    $request_uri = 'https://example.com/route-to-normalize';
+    $request_query = [];
+
+    $event = $this->getGetResponseEventStub($request_uri, http_build_query($request_query), HttpKernelInterface::MASTER_REQUEST, TRUE);
+    // We set '_disable_route_normalizer' as a request attribute and expect to leave onKernelRequestRedirect at the beginning,
+    // i.e. $this->redirectChecker->canRedirect($request) should never be called.
+    $subscriber = $this->getSubscriber($request_uri, TRUE, FALSE);
+    $subscriber->onKernelRequestRedirect($event);
+  }
+
+  /**
+   * @covers ::onKernelRequestRedirect
+   * @dataProvider getTestUrls
+   */
+  public function testOnKernelRequestRedirect($request_uri, $request_query, $expected, $expect_normalization) {
+    $event = $this->getGetResponseEventStub($request_uri, http_build_query($request_query));
+    $subscriber = $this->getSubscriber($request_uri);
+    $subscriber->onKernelRequestRedirect($event);
+
+    if ($expect_normalization) {
+      $response = $event->getResponse();
+      $this->assertEquals($expected, $response->getTargetUrl());
+    }
+  }
+
+  /**
+   * Data provider for testOnKernelRequestRedirect().
+   */
+  public function getTestUrls() {
+    return [
+      ['https://example.com/route-to-normalize', [], 'https://example.com/route-to-normalize', FALSE],
+      ['https://example.com/route-to-normalize', ['key' => 'value'], 'https://example.com/route-to-normalize?key=value', FALSE],
+      ['https://example.com/index.php/', ['q' => 'node/1'], 'https://example.com/?q=node/1', TRUE],
+    ];
+  }
+
+  /**
+   * Create a RouteNormalizerRequestSubscriber object.
+   *
+   * @param string $request_uri
+   *   The return value for the generateFromRoute method.
+   * @param bool $enabled
+   *   Flag indicating if the normalizer shoud be enabled.
+   * @param bool $call_expected
+   *   If true, canRedirect() and other methods should be called once.
+   *
+   * @return \Drupal\redirect\EventSubscriber\RouteNormalizerRequestSubscriber
+   */
+  protected function getSubscriber($request_uri, $enabled = TRUE, $call_expected = TRUE) {
+    return new RouteNormalizerRequestSubscriber(
+      $this->getUrlGeneratorStub($request_uri, $call_expected),
+      $this->getPathMatcherStub($call_expected),
+      $this->getConfigFactoryStub([
+        'redirect.settings' => [
+          'route_normalizer_enabled' => $enabled,
+          'default_status_code' => 301,
+        ],
+      ]),
+      $this->getRedirectCheckerStub($call_expected)
+    );
+  }
+
+  /**
+   * Gets the UrlGenerator mock object.
+   *
+   * @param string $request_uri
+   *   The return value for the generateFromRoute method.
+   * @param bool $call_expected
+   *   If true, we expect generateFromRoute() to be called once.
+   *
+   * @return \Drupal\Core\Routing\UrlGeneratorInterface|PHPUnit_Framework_MockObject_MockObject
+   */
+  protected function getUrlGeneratorStub($request_uri, $call_expected = TRUE) {
+    $url_generator = $this->getMockBuilder('\Drupal\Core\Routing\UrlGeneratorInterface')
+      ->getMock();
+
+    $options = ['absolute' => TRUE];
+
+    $expectation = $call_expected ? $this->once() : $this->never();
+
+    $url_generator->expects($expectation)
+      ->method('generateFromRoute')
+      ->with('<current>', [], $options)
+      ->willReturn($request_uri);
+    return $url_generator;
+  }
+
+  /**
+   * Gets the PathMatcher mock object.
+   *
+   * @param bool $call_expected
+   *   If true, we expect isFrontPage() to be called once.
+   *
+   * @return \Drupal\Core\Path\PathMatcherInterface|PHPUnit_Framework_MockObject_MockObject
+   */
+  protected function getPathMatcherStub($call_expected = TRUE) {
+    $path_matcher = $this->getMockBuilder('\Drupal\Core\Path\PathMatcherInterface')
+      ->getMock();
+
+    $expectation = $call_expected ? $this->once() : $this->never();
+
+    $path_matcher->expects($expectation)
+      ->method('isFrontPage')
+      ->withAnyParameters()
+      ->willReturn(FALSE);
+    return $path_matcher;
+  }
+
+  /**
+   * Gets the RedirectChecker mock object.
+   *
+   * @param bool $call_expected
+   *   If true, we expect canRedirect() to be called once.
+   *
+   * @return \Drupal\redirect\RedirectChecker|PHPUnit_Framework_MockObject_MockObject
+   */
+  protected function getRedirectCheckerStub($call_expected = TRUE) {
+    $redirect_checker = $this->getMockBuilder('\Drupal\redirect\RedirectChecker')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $expectation = $call_expected ? $this->once() : $this->never();
+
+    $redirect_checker->expects($expectation)
+      ->method('canRedirect')
+      ->withAnyParameters()
+      ->willReturn(TRUE);
+    return $redirect_checker;
+  }
+
+  /**
+   * Returns a GET response event object.
+   *
+   * @param string $path_info
+   *   The path of the request.
+   * @param array $query_string
+   *   The query string of the request.
+   * @param int $request_type
+   *   The request type of the request.
+   * @param bool $set_request_attribute
+   *   If true, the request attribute '_disable_route_normalizer' will be set.
+   *
+   * @return \Symfony\Component\HttpKernel\Event\GetResponseEvent
+   */
+  protected function getGetResponseEventStub($path_info, array $query_string, $request_type = HttpKernelInterface::MASTER_REQUEST, $set_request_attribute = FALSE) {
+    $request = Request::create($path_info . '?' . $query_string, 'GET', [], [], [], ['SCRIPT_NAME' => 'index.php', 'SCRIPT_FILENAME' => 'index.php']);
+
+    if ($set_request_attribute === TRUE) {
+      $request->attributes->add(['_disable_route_normalizer' => TRUE]);
+    }
+
+    $http_kernel = $this->getMockBuilder('\Symfony\Component\HttpKernel\HttpKernelInterface')
+      ->getMock();
+    return new GetResponseEvent($http_kernel, $request, $request_type);
+  }
+
+}