def test_remove_tag_undo_redo(filled_database):
    foo = Tag('foo')
    foo.id = 1
    fourth_entry = filled_database.get_entry_by_id(4)
    assert foo in fourth_entry.tags
    filled_database.remove_tag(fourth_entry, 'foo')
    assert foo not in fourth_entry.tags
    assert foo in filled_database.tags
    filled_database.undo()
    assert foo in fourth_entry.tags
    assert foo in filled_database.tags
    filled_database.redo()
    assert foo not in fourth_entry.tags
    assert foo in filled_database.tags
    eighth_entry = filled_database.get_entry_by_id(8)
    filled_database.remove_tag(eighth_entry, 'foo')
    assert foo not in eighth_entry.tags
    assert foo not in filled_database.tags
    filled_database.undo()
    assert foo not in fourth_entry.tags
    assert foo in eighth_entry.tags
    assert foo in filled_database.tags
    filled_database.redo()
    assert foo not in eighth_entry.tags
    assert foo not in filled_database.tags

def test_get_existing_tag(database):
    entry = DatabaseEntry()
    database.tag(entry, 'tag')
    database.add(entry)
    expected_tag = Tag('tag')
    expected_tag.id = 1
    assert database.get_tag('tag') == expected_tag

def test_getitem_exceeding_range(filled_database):
    entries = filled_database[7:1000]
    foo = Tag("foo")
    foo.id = 1
    bar = Tag("bar")
    bar.id = 2
    assert entries == [DatabaseEntry(id=8, tags=[foo]), DatabaseEntry(id=9), DatabaseEntry(id=10, tags=[bar])]

def test_getitem_negative_indices_slice(filled_database):
    entries = filled_database[-2:-8:-2]
    bar = Tag('bar')
    bar.id = 2
    assert entries == [
        DatabaseEntry(id=9),
        DatabaseEntry(id=7),
        DatabaseEntry(id=5, tags=[bar])]

def test_remove_many_entries(filled_database):
    bar = Tag("bar")
    bar.id = 2
    # required to check if `remove_many` adds any entries to undo-history
    filled_database.clear_histories()
    filled_database.remove_many(filled_database[:8])
    assert len(filled_database) == 2
    assert list(filled_database) == [DatabaseEntry(id=9), DatabaseEntry(id=10, tags=[bar])]
    filled_database.undo()
    assert len(filled_database) == 10
    with pytest.raises(EmptyCommandStackError):
        filled_database.undo()

def test_query(filled_database):
    foo = Tag('foo')
    foo.id = 1
    bar = Tag('bar')
    bar.id = 2
    entries = filled_database.query(
        attrs.Tag('foo') | attrs.Tag('bar'), sortby='id')
    assert len(entries) == 4
    assert entries == [
        DatabaseEntry(id=4, tags=[foo]),
        DatabaseEntry(id=5, tags=[bar]),
        DatabaseEntry(id=8, tags=[foo]),
        DatabaseEntry(id=10, tags=[bar])]

def test_query(filled_database):
    foo = Tag("foo")
    foo.id = 1
    bar = Tag("bar")
    bar.id = 2
    entries = filled_database.query(attrs.Tag("foo") | attrs.Tag("bar"), sortby="id")
    assert len(entries) == 4
    assert entries == [
        DatabaseEntry(id=4, tags=[foo]),
        DatabaseEntry(id=5, tags=[bar]),
        DatabaseEntry(id=8, tags=[foo]),
        DatabaseEntry(id=10, tags=[bar]),
    ]

def test_remove_tag(filled_database):
    foo = Tag("foo")
    foo.id = 1
    fourth_entry = filled_database.get_entry_by_id(4)
    assert foo in fourth_entry.tags
    eighth_entry = filled_database.get_entry_by_id(8)
    assert foo in eighth_entry.tags
    filled_database.remove_tag(fourth_entry, "foo")
    assert foo not in fourth_entry.tags
    assert foo in filled_database.tags
    filled_database.remove_tag(eighth_entry, "foo")
    assert foo not in eighth_entry.tags
    assert foo not in filled_database.tags

def test_getitem_custom(filled_database):
    entries = filled_database[1:5:2]
    foo = Tag('foo')
    foo.id = 1
    assert entries == [
        DatabaseEntry(id=2), DatabaseEntry(id=4, tags=[foo])]