#305_write unit test for UIComponent completion

Author: iamdylanngo

tests/com/magento/idea/magento2plugin/completion/xml/XLayoutContainerCompletionRegistrarTest.java renamed to tests/com/magento/idea/magento2plugin/completion/xml/LayoutContainerCompletionRegistrarTest.java

@@ -7,7 +7,7 @@
 
 import com.magento.idea.magento2plugin.magento.files.LayoutXml;
 
-public class XLayoutContainerCompletionRegistrarTest extends CompletionXmlFixtureTestCase {
+public class LayoutContainerCompletionRegistrarTest extends CompletionXmlFixtureTestCase {
 
     /**
      * The `name` attribute of the `referenceContainer` tag in layout XML must