找不到如何使用 pytest 测试此代码

Question

I have the following piece of code and I need to test it using pytest mocker. I have tried tens of various combinations but couldn't find one that works. Can you help?

    def authenticate(self, account_id, region, role, credential_file) -> dict:
        self.aws_credentials = get_credentials(credential_file)
        sts_client = boto3.client(
            "sts",
            aws_access_key_id=self.aws_credentials["key"],
            aws_secret_access_key=self.aws_credentials["value"],
            region_name=region,
        )
        assumed_role = sts_client.assume_role(
            RoleArn=f"arn:aws:iam::{account_id}:role/{role}",
            RoleSessionName="AssumeRoleSession1",
        )
        return assumed_role["Credentials"]

First call to get_credentials is easily patched. But then I need to mock the STS client and then mock again the assume_role call. I tried this but get an assertion error

def test_authenticate(self, mocker):
    def fake_assume_role(RoleArn: str = "", RoleSessionName: str = ""):
        return {"Credentials": "Valid Credentials"}
        
    mocker.patch(
        "get_credentials",
        return_value={"value": "valid_value", "key": "valid_key"},
    )
    mock_sts_client = mocker.patch(
        "boto3.client")
    mock_sts_client.assume_role = fake_assume_role
    auth = pylib.authentication.AWSAuthentication()
    actual_creds = auth.authenticate(
        account_id="123456789012",
        region="far-west-1",
        role="Cyrano",
        credential_file="cred.json"
        )
    assert actual_creds == "Valid Credentials"

Answer 1

I did this and it worked for me:

def test_authenticate(self, mocker):
    mocker.patch(
        "get_credentials",
        return_value={"value": "valid_value", "key": "valid_key"},
    )
    mock_sts_client = mocker.Mock()
    mock_sts_client.assume_role.return_value = {"Credentials": "Valid Credentials"}
    mocker.patch('boto3.client', return_value=mock_sts_client)
    auth = AWSAuthentication()
    actual_creds = auth.authenticate(
        account_id="123456789012",
        region="far-west-1",
        role="Cyrano",
        credential_file="cred.json"
        )
    assert actual_creds == "Valid Credentials"