### Question:
AssetList implements IsElement { public void onPageNumberChange(final int pageNumber) { if (pageNumber > 0) { this.pageNumber = pageNumber; } else { this.pageNumber = 1; } command.execute(); } @Inject  AssetList(final View view); void resetPageRangeIndicator(); void clear(); void add(final HTMLElement element); void showEmptyState(final String topic,
                               final String message); Integer getStep(); void onChangeAmountOfItemsShown(final int step); void onToFirstPage(); void onToNextPage(); void onToPrevious(); void onPageNumberChange(final int pageNumber); @Override HTMLElement getElement(); void addChangeHandler(final Command command); int getFirstIndex();  }### Answer:
@Test public void zeroOrNegativeValuesAreNotAllowedAsPageNumber() throws Exception { assetList.onPageNumberChange(-1); verify(view).setPageNumber(1); }