Follow up StatusTextMixinTest

Author: kevzlou7979

gwt-material/src/test/java/gwt/material/design/client/mixin/StatusTextMixinTest.java

@@ -89,6 +89,7 @@ protected void runTest(StatusTextMixin<MaterialTextBox, MaterialLabel> mixin) {
         mixin.clearStatusText();
 
         // Then
+        assertEquals(HELPER_TEXT, label.getText());
         assertFalse(label.getElement().hasClassName(CssName.FIELD_ERROR_LABEL));
         assertFalse(label.getElement().hasClassName(CssName.FIELD_SUCCESS_LABEL));
         assertTrue(label.getElement().hasClassName(CssName.FIELD_HELPER_LABEL));