Improve unit tests

tests/units/Helper/AssetHelperTest.php

@@ -0,0 +1,21 @@
+<?php
+
+require_once __DIR__.'/../Base.php';
+
+use Helper\Asset;
+use Model\Config;
+
+class AssetHelperTest extends Base
+{
+    public function testCustomCss()
+    {
+        $h = new Asset($this->container);
+        $c = new Config($this->container);
+
+        $this->assertEmpty($h->customCss());
+
+        $this->assertTrue($c->save(array('application_stylesheet' => 'p { color: red }')));
+
+        $this->assertEquals('<style>p { color: red }</style>', $h->customCss());
+    }
+}