diff --git a/.idea/php.xml b/.idea/php.xml
index f6e673a..a7994be 100644
--- a/.idea/php.xml
+++ b/.idea/php.xml
@@ -1,3 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project version="4" />
-
+<project version="4">
+  <component name="PhpUnit">
+    <phpunit_settings>
+      <PhpUnitSettings load_method="CUSTOM_LOADER" configuration_file_path="$PROJECT_DIR$/phpunit.xml.dist" custom_loader_path="$PROJECT_DIR$/vendor/autoload.php" phpunit_phar_path="$PROJECT_DIR$/vendor/bin/phpunit" use_configuration_file="true" />
+    </phpunit_settings>
+  </component>
+</project>
\ No newline at end of file
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 017916a..ccb135b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -20,8 +20,11 @@
         <env name="FAIL_PORT" value="9001-9100" />
     </php>
     <testsuites>
-        <testsuite name="WellRESTed Test Suite">
-            <directory>./test/</directory>
+        <testsuite name="unit">
+            <directory>./test/tests/unit/</directory>
+        </testsuite>
+        <testsuite name="integration">
+            <directory>./test/tests/integration/</directory>
         </testsuite>
     </testsuites>
     <filter>
diff --git a/src/pjdietz/WellRESTed/Router.php b/src/pjdietz/WellRESTed/Router.php
index 0f4d202..45a0192 100644
--- a/src/pjdietz/WellRESTed/Router.php
+++ b/src/pjdietz/WellRESTed/Router.php
@@ -136,7 +136,7 @@ class Router implements HandlerInterface
     public function getResponse(RequestInterface $request, array $args = null)
     {
         $response = $this->tryResponse($this->routeTable, $request, $args);
-        if ($response) {
+        if ($response && $response instanceof ResponseInterface) {
             // Check if the router has an error handler for this status code.
             $status = $response->getStatusCode();
             $errorResponse = $this->getErrorResponse($status, $request, $args, $response);
diff --git a/test/src/MockHandler.php b/test/src/MockHandler.php
deleted file mode 100644
index e39712d..0000000
--- a/test/src/MockHandler.php
+++ /dev/null
@@ -1,17 +0,0 @@
-<?php
-
-use pjdietz\WellRESTed\Interfaces\HandlerInterface;
-use pjdietz\WellRESTed\Response;
-
-/**
- * Mini Handler class that allways returns a 200 status code Response.
- */
-class MockHandler implements HandlerInterface
-{
-    public function getResponse(\pjdietz\WellRESTed\Interfaces\RequestInterface $request, array $args = null)
-    {
-        $resp = new Response();
-        $resp->setStatusCode(200);
-        return $resp;
-    }
-}
diff --git a/test/tests/integration/RouterTest.php b/test/tests/integration/RouterTest.php
new file mode 100644
index 0000000..79edcf3
--- /dev/null
+++ b/test/tests/integration/RouterTest.php
@@ -0,0 +1,75 @@
+<?php
+
+namespace pjdietz\WellRESTed\Test\Integration;
+
+use pjdietz\WellRESTed\Router;
+use Prophecy\Argument;
+
+class RouterTest extends \PHPUnit_Framework_TestCase
+{
+    private $request;
+    private $response;
+
+    public function setUp()
+    {
+        $this->request = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\RequestInterface");
+        $this->request->getPath()->willReturn("/");
+        $this->request->getMethod()->willReturn("GET");
+        $this->response = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\ResponseInterface");
+        $this->response->getStatusCode()->willReturn(200);
+        $this->response->getBody()->willReturn("Hello, world!");
+    }
+
+    public function testDispatchesCallable()
+    {
+        $response = $this->response;
+
+        $router = new Router();
+        $router->add("/", function () use ($response) {
+            return $response->reveal();
+        });
+
+        $result = $router->getResponse($this->request->reveal());
+        $this->assertSame($response->reveal(), $result);
+    }
+
+    public function testDispatchesCallableWithArguments()
+    {
+        $response = $this->response;
+        $args = ["cat" => "molly"];
+
+        $router = new Router();
+        $router->add("/", function ($rqst, $args) use ($response) {
+            $response->getBody()->willReturn($args["cat"]);
+            return $response->reveal();
+        });
+
+        $result = $router->getResponse($this->request->reveal(), $args);
+        $this->assertEquals("molly", $result->getBody());
+    }
+
+    /**
+     * @runInSeparateProcess
+     * @preserveGlobalState disabled
+     */
+    public function testStopsDispatchingCallablesAfterFirstNonNull()
+    {
+        $router = new Router();
+        $router->add("/cats/{cat}", function () {
+            echo "Hello, cat!";
+            return true;
+        });
+        $router->add("/cats/{cat}", function () {
+            echo "Hello, cat!";
+        });
+
+        $this->request->getPath()->willReturn("/cats/molly");
+
+        ob_start();
+        $router->getResponse($this->request->reveal());
+        $captured = ob_get_contents();
+        ob_end_clean();
+
+        $this->assertEquals("Hello, cat!", $captured);
+    }
+}
diff --git a/test/ApacheRequestHeadersTest.php b/test/tests/unit/ApacheRequestHeadersTest.php
similarity index 100%
rename from test/ApacheRequestHeadersTest.php
rename to test/tests/unit/ApacheRequestHeadersTest.php
diff --git a/test/ClientTest.php b/test/tests/unit/ClientTest.php
similarity index 94%
rename from test/ClientTest.php
rename to test/tests/unit/ClientTest.php
index 93af958..0cfc012 100644
--- a/test/ClientTest.php
+++ b/test/tests/unit/ClientTest.php
@@ -19,7 +19,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/method.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/method.php");
 
         $server = new ShamServer($host, $port, $script);
 
@@ -57,7 +57,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/headers.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/headers.php");
 
         $server = new ShamServer($host, $port, $script);
 
@@ -92,7 +92,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/body.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/body.php");
         $server = new ShamServer($host, $port, $script);
 
         $rqst = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\RequestInterface");
@@ -125,7 +125,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/formFields.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/formFields.php");
         $server = new ShamServer($host, $port, $script);
 
         $rqst = new Request("http://$host:$port");
@@ -158,7 +158,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/headers.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/headers.php");
         $server = new ShamServer($host, $port, $script);
 
         $rqst = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\RequestInterface");
@@ -181,7 +181,7 @@ class ClientTest extends \PHPUnit_Framework_TestCase
     {
         $host = "localhost";
         $port = $this->getRandomNumberInRange(getenv("PORT"));
-        $script = realpath(__DIR__ . "/sham-routers/headers.php");
+        $script = realpath(__DIR__ . "/../../sham-routers/headers.php");
         $server = new ShamServer($host, $port, $script);
 
         $rqst = $this->prophesize("\\pjdietz\\WellRESTed\\Interfaces\\RequestInterface");
diff --git a/test/HandlerTest.php b/test/tests/unit/HandlerTest.php
similarity index 100%
rename from test/HandlerTest.php
rename to test/tests/unit/HandlerTest.php
diff --git a/test/HandlerUnpackerTest.php b/test/tests/unit/HandlerUnpackerTest.php
similarity index 100%
rename from test/HandlerUnpackerTest.php
rename to test/tests/unit/HandlerUnpackerTest.php
diff --git a/test/MessageTest.php b/test/tests/unit/MessageTest.php
similarity index 100%
rename from test/MessageTest.php
rename to test/tests/unit/MessageTest.php
diff --git a/test/RequestTest.php b/test/tests/unit/RequestTest.php
similarity index 100%
rename from test/RequestTest.php
rename to test/tests/unit/RequestTest.php
diff --git a/test/ResponseTest.php b/test/tests/unit/ResponseTest.php
similarity index 100%
rename from test/ResponseTest.php
rename to test/tests/unit/ResponseTest.php
diff --git a/test/RouteBuilderTest.php b/test/tests/unit/RouteBuilderTest.php
similarity index 100%
rename from test/RouteBuilderTest.php
rename to test/tests/unit/RouteBuilderTest.php
diff --git a/test/RouteTableTest.php b/test/tests/unit/RouteTableTest.php
similarity index 100%
rename from test/RouteTableTest.php
rename to test/tests/unit/RouteTableTest.php
diff --git a/test/RouterTest.php b/test/tests/unit/RouterTest.php
similarity index 100%
rename from test/RouterTest.php
rename to test/tests/unit/RouterTest.php
diff --git a/test/Routes/BaseRouteTest.php b/test/tests/unit/Routes/BaseRouteTest.php
similarity index 100%
rename from test/Routes/BaseRouteTest.php
rename to test/tests/unit/Routes/BaseRouteTest.php
diff --git a/test/Routes/PrefixRouteTest.php b/test/tests/unit/Routes/PrefixRouteTest.php
similarity index 100%
rename from test/Routes/PrefixRouteTest.php
rename to test/tests/unit/Routes/PrefixRouteTest.php
diff --git a/test/Routes/RegexRouteTest.php b/test/tests/unit/Routes/RegexRouteTest.php
similarity index 100%
rename from test/Routes/RegexRouteTest.php
rename to test/tests/unit/Routes/RegexRouteTest.php
diff --git a/test/Routes/RouteFactoryTest.php b/test/tests/unit/Routes/RouteFactoryTest.php
similarity index 100%
rename from test/Routes/RouteFactoryTest.php
rename to test/tests/unit/Routes/RouteFactoryTest.php
diff --git a/test/Routes/StaticRouteTest.php b/test/tests/unit/Routes/StaticRouteTest.php
similarity index 100%
rename from test/Routes/StaticRouteTest.php
rename to test/tests/unit/Routes/StaticRouteTest.php
diff --git a/test/Routes/TemplateRouteTest.php b/test/tests/unit/Routes/TemplateRouteTest.php
similarity index 100%
rename from test/Routes/TemplateRouteTest.php
rename to test/tests/unit/Routes/TemplateRouteTest.php