fix: Validate config only after the options have been set

To avoid an exception when default options are not valid but the new options are.

classes/Config.php

@@ -135,7 +135,6 @@ class Config
     {
         $this->applyOptions($options);
         $this->getEnv();
-        $this->validateOptions();
     }
 
     /**
@@ -216,6 +215,7 @@ class Config
         if (is_file($file)) {
             $options = Yaml::parse(file_get_contents($file));
             self::$instance = new self($options);
+            self::$instance->validateOptions();
         } else {
             throw new Exception("Can't find config file at ".$file);
         }

tests/ConfigTest.php

@@ -41,6 +41,20 @@ class ConfigTest extends BaseTest
         $this->assertConfig($config);
     }
 
+    /**
+     * Test the getInstance function.
+     *
+     * @return void
+     */
+    public function testGetInstanceFromScratch()
+    {
+        Config::destroyInstance();
+
+        $config = Config::getInstance();
+        $this->assertEquals($config->convert, false);
+        $this->assertConfig($config);
+    }
+
     /**
      * Assert that a Config object is correctly instantiated.
      *