test_samples.py 文件源码

def assertQueries(*prefixes):
    "Assert the correct queries are efficiently executed for a block."
    count = len(connection.queries)
    yield
    for prefix, query in itertools.izip_longest(prefixes, connection.queries[count:]):
        assert prefix and query and query['sql'].startswith(prefix), (prefix, query)
        cursor = connection.cursor()
        cursor.execute('EXPLAIN ' + query['sql'])
        plan = ''.join(row for row, in cursor)
        assert prefix == 'INSERT' or 'Index Scan' in plan, (plan, query)