### Question:
FieldLayoutComponent implements FormLayoutComponent,
                                             LayoutDragComponent { public Optional<IsWidget> getContentPart(String partId, RenderingContext componentContext) { return Optional.ofNullable(fieldRenderer.getFieldPartWidget(partId)); } @Inject  FieldLayoutComponent(FieldRendererManager fieldRendererManager, TranslationService translationService); void init(FormRenderingContext renderingContext,
                     FieldDefinition field); @Override String getDragComponentTitle(); @Override IsWidget getPreviewWidget(RenderingContext ctx); @Override IsWidget getShowWidget(RenderingContext ctx); Optional<IsWidget> getContentPart(String partId, RenderingContext componentContext); void addComponentParts(LayoutComponent component); String getFieldId(); String getFormId(); FieldRenderer getFieldRenderer(); FieldDefinition getField(); @PreDestroy void destroy();  }### Answer:
@Test public void testGetContentPart() { RenderingContext renderingContext = mock(RenderingContext.class); Assertions.assertThat(component.getContentPart(PART_1, renderingContext)) .isNotNull() .isPresent(); Assertions.assertThat(component.getContentPart(PART_2, renderingContext)) .isNotNull() .isPresent(); Assertions.assertThat(component.getContentPart(PART_3, renderingContext)) .isNotNull() .isPresent(); Assertions.assertThat(component.getContentPart(UNEXISTING_PART, renderingContext)) .isNotNull() .isNotPresent(); }