moto @mock_ec2 出错 ImportError: cannot import name 'DictLoader'?

Question

我有以下测试代码，

from unittest.mock import Mock, patch

import boto3
import boto3.resources
import boto3.resources.base
import boto3.session
import pytest
from moto import mock_ec2

@pytest.fixture(scope="function")
def aws_credentials():
    """Mocked AWS Credentials for moto."""
    os.environ["AWS_ACCESS_KEY_ID"] = "testing"
    os.environ["AWS_SECRET_ACCESS_KEY"] = "testing"
    os.environ["AWS_SECURITY_TOKEN"] = "testing"
    os.environ["AWS_SESSION_TOKEN"] = "testing"
    os.environ["MOTO_ALLOW_NONEXISTENT_REGION"] = "True"
    os.environ["AWS_DEFAULT_REGION"] = "testing"

@pytest.fixture
def get_session(aws_credentials):
    """boto3 Session"""
    return boto3.session.Session()

# and other tests code

运行良好。但是，我添加以下test_method后出现以下错误

@mock_ec2
def test_get_instances(get_session):
    """Test ...."""

错误是：

ImportError while importing test module 'C:\Users\....\test_n1.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
..\..\..\..\anaconda3\lib\importlib\__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests\unit_tests\test_node.py:85: in <module>
    @mock_ec2
..\..\..\..\anaconda3\lib\site-packages\moto\__init__.py:17: in f
    module = importlib.import_module(module_name, "moto")
..\..\..\..\anaconda3\lib\importlib\__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
..\..\..\..\anaconda3\lib\site-packages\moto\ec2\__init__.py:1: in <module>
    from .models import ec2_backends
..\..\..\..\anaconda3\lib\site-packages\moto\ec2\models.py:29: in <module>
    from moto.core import BaseBackend
..\..\..\..\anaconda3\lib\site-packages\moto\core\__init__.py:4: in <module>
    from .responses import ActionAuthenticatorMixin
..\..\..\..\anaconda3\lib\site-packages\moto\core\responses.py:11: in <module>
    from moto.core.exceptions import DryRunClientError
..\..\..\..\anaconda3\lib\site-packages\moto\core\exceptions.py:2: in <module>
    from jinja2 import DictLoader, Environment
E   ImportError: cannot import name 'DictLoader'

Answer 1

听起来您缺少一些依赖项。确保在安装 moto 时指定您使用的服务：

pip install moto[ec2]

当自行安装 moto (pip install moto) 时，它只会安装基本功能 - 指定您将使用哪些服务来确保它安装所需的依赖项。

查看文档：http://docs.getmoto.org/en/latest/docs/getting_started.html#installing-moto