解决Pytest与Moto测试中DynamoDB上下文隔离的常见陷阱

import pytest
import boto3
from moto import mock_dynamodb
import os

# conftest.py 中的 AWS 凭证设置，确保 moto 正常工作
def pytest_configure(config):
    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["AWS_DEFAULT_REGION"] = "eu-central-1"
    os.environ["AWS_REGION"] = "eu-central-1"

class TestDynamodbClient:

    @pytest.fixture
    def test_table(self):
        with mock_dynamodb():
            table_name = "test_table"
            dynamodb = boto3.resource('dynamodb')

            params = {
                'TableName': table_name,
                'KeySchema': [
                    {'AttributeName': 'id', 'KeyType': 'HASH'},
                ],
                'AttributeDefinitions': [
                    {'AttributeName': 'id', 'AttributeType': 'N'},
                ],
                'ProvisionedThroughput': {
                    'ReadCapacityUnits': 5,
                    'WriteCapacityUnits': 5
                }
            }

            table = dynamodb.create_table(**params)
            table.wait_until_exists()

            # 确认表在 fixture 内部已成功创建
            assert table_name in [t.name for t in dynamodb.tables.all()]
            print(f"Fixture: Table '{table_name}' created and visible.")
            return table_name

    @pytest.mark.integration
    def test_recreate_table__table_exists__recreates_table(self, test_table):
        with mock_dynamodb():  # <-- 问题所在：重复调用 mock_dynamodb()
            # given
            # client = DynamodbClient() # 假设这里有一个客户端类

            dynamodb = boto3.resource('dynamodb')
            # 预期会失败：assert 'test_table' in []
            assert test_table in [t.name for t in dynamodb.tables.all()] 
            print(f"Test: Tables visible: {[t.name for t in dynamodb.tables.all()]}")

            # when
            # client.recreate_table("test_table")

            # then
            # ...

    @pytest.mark.integration
    def test_recreate_table__table_exists__recreates_table(self, test_table):
        # 移除 with mock_dynamodb()，让 fixture 的上下文生效
        # given
        # client = DynamodbClient() # 假设这里有一个客户端类

        dynamodb = boto3.resource('dynamodb')
        # 现在这个断言会通过
        assert test_table in [t.name for t in dynamodb.tables.all()]
        print(f"Test: Tables visible: {[t.name for t in dynamodb.tables.all()]}")

        # when
        # client.recreate_table("test_table")

        # then
        # ...