### Question:
ClearCanvasCommand extends AbstractCanvasCommand { @Override public CommandResult<CanvasViolation> execute(final AbstractCanvasHandler context) { context.clearCanvas(); return buildResult(); }  @Override CommandResult<CanvasViolation> execute(final AbstractCanvasHandler context); @Override CommandResult<CanvasViolation> undo(final AbstractCanvasHandler context); @Override String toString();  }### Answer:
@Test public void testExecute() { final CommandResult<CanvasViolation> result = tested.execute(canvasHandler); assertNotEquals(CommandResult.Type.ERROR, result.getType()); verify(canvasHandler, times(1)).clearCanvas(); }