@Override
    public void rotate(IndexSet indexSet) {
        indexRotator.rotate(indexSet, this::shouldRotate);
    }
@Test
    public void shouldRotateThrowsISEIfIndexSetIdIsNull() {
        when(indexSet.getConfig()).thenReturn(indexSetConfig);
        when(indexSetConfig.id()).thenReturn(null);
        when(indexSet.getNewestIndex()).thenReturn(IGNORED);

        expectedException.expect(IllegalStateException.class);
        expectedException.expectMessage("Index set ID must not be null or empty");

        rotationStrategy.rotate(indexSet);
    }