def test_batch_db_read_through_delete_after_modify(base_db):
base_db[b'modify-then-delete'] = b'original'
batch_db = BatchDB(base_db, read_through_deletes=True)
batch_db.set(b'modify-then-delete', b'new-val')
assert batch_db[b'modify-then-delete'] == b'new-val'
batch_db.delete(b'modify-then-delete')
assert batch_db[b'modify-then-delete'] == b'original'
batch_db.commit(apply_deletes=False)
assert base_db[b'modify-then-delete'] == b'original'
def test_batch_db_read_through_delete(base_db):
base_db[b'read-through-deleted'] = b'still-here'
batch_db = BatchDB(base_db, read_through_deletes=True)
batch_db.set(b'only-in-batch', b'will-disappear')
batch_db.delete(b'read-through-deleted')
batch_db.delete(b'only-in-batch')
assert b'read-through-deleted' in batch_db
assert batch_db[b'read-through-deleted'] == b'still-here'
assert b'only-in-batch' not in batch_db
with pytest.raises(KeyError):
batch_db[b'only-in-batch']
batch_db.commit(apply_deletes=False)
assert base_db[b'read-through-deleted'] == b'still-here'
# deleted batch data should never get pushed to the underlying
assert b'only-in-batch' not in base_db
