Don't do any caching with TTL is 0

Closes #12

src/Router.php

@@ -72,6 +72,15 @@ public function __construct(Dispatcher $events, Container $container = null)
      */
     public function cache($filename, Closure $callback, $cacheMinutes = 1440)
     {
+        // If $cacheMinutes is 0 or lower, there is no need to cache anything.
+        if ($cacheMinutes <= 0) {
+            // Call closure to define routes that should be cached.
+            call_user_func($callback, $this);
+
+            // No cache key.
+            return null;
+        }
+
         $cacher = $this->container['cache'];
         $cacheKey = $this->getCacheKey($filename);
 

tests/IntegrationTest.php

@@ -160,6 +160,19 @@ public function testCacheRoutes()
         $this->assertEquals(1, $router->getRoutes()->count(), 'Routes must be obtained from cache');
     }
 
+    public function testCacheRoutesNoTtl()
+    {
+        $router = $this->getRouter();
+
+        $key = $router->cache(__FILE__, function () use ($router) {
+            $router->get('/', 'HomeController@actionIndex');
+        }, 0);
+
+        $this->assertNull($key, 'Cache key should be null with TTL=0');
+        $this->assertFalse($this->app->cache->has($key), 'Key should not be stored in cache');
+        $this->assertEquals(1, $router->getRoutes()->count(), 'Route must be added to router');
+    }
+
     public function testAllMethodsWorks()
     {
         $methods = array('get', 'post', 'put', 'patch', 'delete');