pytest处理yml用例嵌套参数关联

在 YAML 用例中，可以使用占位符来关联嵌套参数。这种方式可以让你在一个地方定义某个参数，然后在其他地方引用它。这在处理复杂的嵌套结构时尤其有用。

以下是如何在 YAML 文件中实现嵌套参数的关联的示例。

1. 更新 YAML 文件

这里我们将定义一个用户的详细信息，并在多个地方引用这些参数。

test_cases.yml

# test_cases.yml
user_details:
  name: "John Doe"
  email: "john.doe@example.com"
  details:
    age: 30
    address:
      city: "New York"
      zip: "10001"
    contacts:
      - type: "phone"
        number: "123-456-7890"
      - type: "email"
        number: "john.doe@example.com"

tests:
  - name: "Create User"
    method: "POST"
    endpoint: "/api/users"
    payload:
      name: ${user_details.name}
      email: ${user_details.email}
      details:
        age: ${user_details.details.age}
        address:
          city: ${user_details.details.address.city}
          zip: ${user_details.details.address.zip}
        contacts: ${user_details.details.contacts}
    expected_status: 201
    id: "user_id"

  - name: "Get User"
    method: "GET"
    endpoint: "/api/users/{user_id}"
    expected_status: 200
    depends_on: "Create User"
    validate:
      field: "details.age"
      condition: "greater_than"
      value: 18

  - name: "Get User City"
    method: "GET"
    endpoint: "/api/users/{user_id}"
    expected_status: 200
    depends_on: "Get User"
    validate:
      field: "details.address.city"
      condition: "equals"
      value: "New York"

  - name: "Get User Phone"
    method: "GET"
    endpoint: "/api/users/{user_id}"
    expected_status: 200
    depends_on: "Get User"
    validate:
      field: "details.contacts.0.number"
      condition: "equals"
      value: "123-456-7890"

2. 处理占位符的代码

你需要在加载 YAML 文件时处理这些占位符。可以使用简单的文本替换来实现。

import yaml
import requests
import pytest
import re

def load_test_cases(file_path):
    """从 YAML 文件加载测试用例。"""
    with open(file_path, 'r') as file:
        data = yaml.safe_load(file)
        return data

def resolve_placeholders(data, context):
    """解析 YAML 数据中的占位符。"""
    if isinstance(data, dict):
        return {key: resolve_placeholders(value, context) for key, value in data.items()}
    elif isinstance(data, list):
        return [resolve_placeholders(item, context) for item in data]
    elif isinstance(data, str) and data.startswith("${") and data.endswith("}"):
        placeholder = data[2:-1]  # 去掉 ${ 和 }
        return context.get(placeholder, data)  # 返回上下文中的值或原字符串
    return data

@pytest.fixture(scope="session")
def base_url():
    return "http://localhost:5000"  # 替换为你的 API 基础 URL

def run_test_case(base_url, test_case, previous_results):
    """执行单个测试用例并验证响应。"""
    url = f"{base_url}{test_case['endpoint']}"
    method = test_case['method']
    expected_status = test_case['expected_status']

    # 替换 URL 中的 {user_id}
    for key in previous_results:
        if f'{{{key}}}' in url:
            url = url.replace(f'{{{key}}}', str(previous_results[key]))

    # 发送请求
    response = requests.request(method, url, json=test_case.get('payload', {}))

    # 断言状态码
    assert response.status_code == expected_status

    # 记录结果
    if 'id' in test_case:
        previous_results[test_case['id']] = response.json().get('id')  # 记录创建结果的 ID

    # 验证返回字段
    if 'validate' in test_case:
        validate_response(response.json(), test_case['validate'])

def validate_response(response_data, validation):
    """验证响应数据中的字段值是否满足特定条件。"""
    field_path = validation['field'].split('.')
    actual_value = response_data

    for field in field_path:
        if isinstance(actual_value, dict) and field in actual_value:
            actual_value = actual_value[field]
        elif isinstance(actual_value, list) and field.isdigit():
            actual_value = actual_value[int(field)]
        else:
            pytest.fail(f"Field '{validation['field']}' not found in response: {response_data}")

    # 执行条件验证
    condition = validation['condition']
    value = validation['value']

    if condition == "equals":
        assert actual_value == value, f"Expected {validation['field']} to be '{value}', but got '{actual_value}'"
    elif condition == "contains":
        assert value in actual_value, f"Expected {validation['field']} to contain '{value}', but got '{actual_value}'"
    elif condition == "greater_than":
        assert actual_value > value, f"Expected {validation['field']} to be greater than '{value}', but got '{actual_value}'"
    elif condition == "less_than":
        assert actual_value < value, f"Expected {validation['field']} to be less than '{value}', but got '{actual_value}'"

def test_api():
    """主测试函数，执行所有测试用例。"""
    data = load_test_cases('test_cases.yml')
    context = data['user_details']  # 获取用户详情作为上下文
    test_cases = data['tests']

    # 解析占位符
    for test_case in test_cases:
        if 'payload' in test_case:
            test_case['payload'] = resolve_placeholders(test_case['payload'], context)

    previous_results = {}
    skip_tests = set()  # 存储需要跳过的测试用例名称

    for test_case in test_cases:
        if 'depends_on' in test_case and test_case['depends_on'] in skip_tests:
            pytest.skip(f"Skipping '{test_case['name']}' due to failure in '{test_case['depends_on']}'.")

        try:
            run_test_case(base_url(), test_case, previous_results)
        except AssertionError as e:
            print(f"Test case '{test_case['name']}' failed: {str(e)}")
            skip_tests.add(test_case['name'])  # 将当前测试标记为跳过

代码解释

1. YAML 文件：

   • 使用 ${} 语法来定义占位符，引用 user_details 中的参数。

2. 解析占位符：

   • 使用 resolve_placeholders 函数递归地解析 YAML 数据中的占位符，查找上下文中的值替换占位符。

3. 上下文管理：

   • 在 test_api 函数中，将 user_details 加载到上下文中，并在解析测试用例的 payload 时引用这些值。

3. 运行测试

确保你已经安装了 pytest 和 requests 库。可以使用以下命令运行测试：

pytest your_test_script.py

总结

通过这种方式，你可以在 YAML 测试用例中灵活地引用嵌套参数，这样可以提高测试用例的可读性和可维护性。使用占位符可以避免重复定义相同的参数，简化测试用例的管理。