# First we have a function
def get_book_by_author_name(db, name):
    autor_id = db.execute(
        "SELECT id FROM users where name = :name;",
        {'name': name}).fetchval()
    return db.execute(
        "select title from books where author_id = :id limit 1",
        {'id': author_id}
    ).fetchval()

# Then we define our expectations to the function. Asynchronous database
# drivers are also supported by the `DBMockAsync` and `DBMockDatabases`
# classes.
from db_mock import DBMockSync
mock = (
    DBMockSync()
    .expect_stmt("select id from users where name = :name",
                 {'name': 'Douglas Adams'})
    .expect_result([(42,)])
    .expect_stmt("select title from books where author_id = :id limit 1",
                 {'id': 42})
    .expect_result([('The Hitchhikers Guide To The Galaxy',)])
)

# Then we run the function. If not all SQL queries are executed in the
# expected order, an exception will be raised.
with mock as db:
    title = get_book_by_author_name(db, 'Douglas Adams')
    assert title == u'The Hitchikers Guide To The Galaxy'