PluginCenterController implements Initializable { protected boolean isValueValid(final String value) { return value != null && !value.trim().isEmpty(); }  void validatePluginsConfiguration(); @Override void initialize(URL location, ResourceBundle resources);  }
@Test public void isManifestAttributeInvalidWhenNull() { assertFalse(controller.isValueValid(null)); }
@Test public void isManifestAttributeInvalidWhenEmpty() { assertFalse(controller.isValueValid("")); }
@Test public void isManifestAttributeInvalidWhenOnlySpaces() { assertFalse(controller.isValueValid(" ")); }