@Test
public void fetchItems() {
itemProvider.addItems(FIRST_ITEM, SECOND_ITEM, THIRD_ITEM, FOURTH_ITEM, FIFTH_ITEM, SIXTH_ITEM);
timeline.setFetchCount(2);
timeline.fetchItems();
timeline.fetchItems();
List<Item> actual = timeline.getItems();
assertArrayEquals(
new Item[] {SIXTH_ITEM, FIFTH_ITEM, FOURTH_ITEM, THIRD_ITEM}, actual.toArray(new Item[2]));
}
@Test
public void fetchItemsIfNonAvailable() throws IOException {
timeline.fetchItems();
List<Item> actual = timeline.getItems();
assertTrue(actual.isEmpty());
verify(sessionStorage).storeTop(null);
}
@Test
public void fetchItemWithRuntimeExceptionOnStoreTop() throws IOException {
RuntimeException cause = new RuntimeException();
doThrow(cause).when(sessionStorage).storeTop(any(Item.class));
Throwable actual = thrownBy(() -> timeline.fetchItems());
assertNotNull(actual);
assertSame(cause, actual);
}
@Test
public void fetchItemsIfFetchCountExceedsAvailableItems() throws IOException {
itemProvider.addItems(FIRST_ITEM, SECOND_ITEM);
timeline.fetchItems();
List<Item> actual = timeline.getItems();
assertArrayEquals(new Item[] {SECOND_ITEM, FIRST_ITEM}, actual.toArray(new Item[2]));
verify(sessionStorage).storeTop(SECOND_ITEM);
}
@Test
public void fetchFirstItemsWithoutTopItemToRecover() throws IOException {
itemProvider.addItems(FIRST_ITEM, SECOND_ITEM, THIRD_ITEM, FOURTH_ITEM);
timeline.setFetchCount(2);
timeline.fetchItems();
List<Item> actual = timeline.getItems();
assertArrayEquals(new Item[] {FOURTH_ITEM, THIRD_ITEM}, actual.toArray(new Item[2]));
verify(sessionStorage).storeTop(FOURTH_ITEM);
}
@Test
public void fetchItemWithExceptionOnStoreTop() throws IOException {
IOException cause = new IOException();
doThrow(cause).when(sessionStorage).storeTop(any(Item.class));
Throwable actual = thrownBy(() -> timeline.fetchItems());
assertNotNull(actual);
assertTrue(actual instanceof IllegalStateException);
assertSame(cause, actual.getCause());
assertEquals(Timeline.ERROR_STORE_TOP, actual.getMessage());
}