### Question:
DecimalBox implements IsWidget,
                                   HasValue<Double> { public void setPlaceholder(String placeHolder) { view.setPlaceholder(placeHolder); } @Inject  DecimalBox(DecimalBoxView view); @Override Double getValue(); @Override void setValue(Double value); @Override void setValue(Double value,
                         boolean fireEvents); @Override HandlerRegistration addValueChangeHandler(ValueChangeHandler<Double> valueChangeHandler); @Override void fireEvent(GwtEvent<?> event); @Override Widget asWidget(); void notifyValueChange(String value); void setEnabled(boolean enabled); boolean isInvalidKeyCode(int key,
                                    boolean isShiftPressed); void setId(String id); void setPlaceholder(String placeHolder); void setMaxLength(Integer maxLength);  }### Answer:
@Test public void testSetPlaceholder() { String placeholder = "Random placeholder"; decimalBox.setPlaceholder(placeholder); verify(view).setPlaceholder(eq(placeholder)); }