    @Test
    public void isExpandableGroup() throws Exception {

        // zero
        assertThat(ItemIdComposer.isExpandableGroup(0L), is(false));

        // NO_ID
        assertThat(ItemIdComposer.isExpandableGroup(RecyclerView.NO_ID), is(false));

        // not group - 1
        assertThat(ItemIdComposer.isExpandableGroup(ItemIdComposer.BIT_MASK_CHILD_ID >> 1), is(false));

        // not group - 2
        assertThat(ItemIdComposer.isExpandableGroup(ItemIdComposer.BIT_MASK_CHILD_ID & ~1), is(false));

        // is group - 1
        assertThat(ItemIdComposer.isExpandableGroup(ItemIdComposer.BIT_MASK_CHILD_ID), is(true));

        // is group - 2
        assertThat(ItemIdComposer.isExpandableGroup(ItemIdComposer.BIT_MASK_GROUP_ID | ItemIdComposer.BIT_MASK_CHILD_ID), is(true));
    }