### Question:
SubFormWidget extends Composite implements TakesValue<Object>,
                                                        IsNestedModel,
                                                        NeedsFlush { public void setReadOnly(boolean readOnly) { formRenderer.switchToMode(readOnly ? RenderMode.READ_ONLY_MODE : RenderMode.EDIT_MODE); }  void render(FormRenderingContext renderingContext); @Override Object getValue(); @Override void setValue(Object value); @Override void clear(); @Override void flush(); @Override void addFieldChangeHandler(FieldChangeHandler handler); void setReadOnly(boolean readOnly); boolean isValid();  }### Answer:
@Test public void testSetReadOnly() { subFormWidget.setReadOnly(true); verify(formRenderer).switchToMode(eq(RenderMode.READ_ONLY_MODE)); subFormWidget.setReadOnly(false); verify(formRenderer).switchToMode(eq(RenderMode.EDIT_MODE)); }