如何在单元测试中模拟parameterNotFoundBotO3异常？

Question

我想测试一些错误处理逻辑，所以我想在单元测试中模拟特定的异常类型。我在模仿对boto3的调用，但是我想用这个mock来引发一个ParameterNotFound异常。我正在测试的代码follows this pattern：

boto3_client = boto3.client('ssm')
try:
    temp_var = boto3_client.get_parameter(Name="Something not found")['Parameter']['Value']
except boto3_client.exceptions.ParameterNotFound:
    ... [logic I want to test]

我已经创建了一个unittest模拟，但是我不知道如何使它引发异常，因为这个ParameterNotFound异常。我尝试了以下方法，但没有成功，因为它在计算except子句时得到“exceptions must derivate from the base class”：

^{pr2}$

如何在单元测试中模拟parameterNotFoundBotO3异常？在

Answer 1

我想问题是我误解了boto3是如何引发异常的。我在这里找到了一个解释：https://github.com/boto/boto3/issues/1262在“ClientError的结构”下

Structure of a ClientError

Within ClientError (but not BotoCoreError), there will be an operation_name attribute (should be a str) and a response attribute (should be a dict). The response attribute should have the following form (example from a malformed ec2.DescribeImages call):

还有这里：https://codeday.me/en/qa/20190306/12210.html

{
    "Error": {
        "Code": "InvalidParameterValue",
        "Message": "The filter 'asdfasdf' is invalid"
    },
    "ResponseMetadata": {
        "RequestId": "aaaabbbb-cccc-dddd-eeee-ffff00001111",
        "HTTPStatusCode": 400,
        "HTTPHeaders": {
            "transfer-encoding": "chunked",
            "date": "Fri, 01 Jan 2100 00:00:00 GMT",
            "connection": "close",
            "server": "AmazonEC2"
        },
        "RetryAttempts": 0
    }
}

听起来异常是作为一个ClientError抛出的，它有一个ParameterNotFound错误代码，所以我需要将其更改为

^{pr2}$

然后呢

except ClientError as e:

在嘲讽中，我需要引发一个ClientError，它的参数notfound作为代码：

raise botocore.exceptions.ClientError({"Error": {"Code": "ParameterNotFound","Message": "The parameter was not found"}}, {...})