C# 为对象列表创建 Mock Configuration.GetSection(“Section:SubSection”)

Question

Objective

使用 Moq 和 XUnit 创建一个模拟对象，用于加载特定部分“Character/Skills”以增强单元测试的覆盖率。

SUT（在某些时候），加载设置的方式

var skills = Configuration.GetSection(“Character:Skills”);

来自以下应用程序设置：

{
    "dummyConfig1": {
        "Description": "bla bla bla...",
    },
    "Character": {
    "Name": "John Wick",
    "Description": "A retired hitman seeking vengeance for the killing of the dog given to him...",
    "Skills": [
        {
        "Key": "CQC Combat",
        "Id": "15465"
        },
        {
        "Key": "Firearms",
        "Id": "14321"
        },
        {
        "Key": "Stealth",
        "Id": "09674"
        },
        {
        "Key": "Speed",
        "Id": "10203"
        }
    ],
    "DummyConf2": "more bla bla bla..."
}

之前的阅读

阅读这些帖子（以及其他其他帖子，作为谷歌搜索的结果），我注意到我们只能使用原始的“字符串”数据类型或者 new Mock 对象（没有设置）：

Stack Overflow - how to mock Configuration.GetSection(“foo:bar”),
Mocking IConfiguration extension method
Mocking IConfiguration Getvalue() extension method in Unit Test

约束： 将 appSetting 文件复制到 TestProject（或创建 MemoryStream）以加载真实设置可以解决这种情况，但测试将改为“集成” “单位”；因为存在 I/O 依赖关系。

方法

代码的想法（稍后显示）是模拟每个属性（key/id），然后将它们合并到类似于此的树中：

"字符" ------ 要读取的配置，使用 GetSection() 然后 Get<T>()
- "技能" ------ 合并属性的配置列表
  - "Key" - "CQC Combat" ------ 原始值1
  - "Id" - "15465" ------ 原始值 2

代码

var skillsConfiguration = new List<SkillsConfig>
{
    new SkillsConfig { Key = "CQC Combat"   , Id = "15465" },
    new SkillsConfig { Key = "Firearms"     , Id = "14321" },
    new SkillsConfig { Key = "Stealh"       , Id = "09674" },
    new SkillsConfig { Key = "Speed"        , Id = "10203" },
};

var configurationMock = new Mock<IConfiguration>();
var mockConfSections = new List<IConfigurationSection>();

foreach (var skill in skillsConfiguration)
{
    var index = skillsConfiguration.IndexOf(skill);

    //Set the Key string value
    var mockConfSectionKey = new Mock<IConfigurationSection>();
    mockConfSectionKey.Setup(s => s.Path).Returns($"Character:Skills:{index}:Key");
    mockConfSectionKey.Setup(s => s.Key).Returns("Key");
    mockConfSectionKey.Setup(s => s.Value).Returns(skill.Key);

    //Set the Id string value
    var mockConfSectionId = new Mock<IConfigurationSection>();
    mockConfSectionId.Setup(s => s.Path).Returns($"Character:Skills:{index}:Id");
    mockConfSectionId.Setup(s => s.Key).Returns("Id");
    mockConfSectionId.Setup(s => s.Value).Returns(skill.Id);

    //Merge the attribute "key/id" as Configuration section list
    var mockConfSection = new Mock<IConfigurationSection>();                
    mockConfSection.Setup(s => s.Path).Returns($"Character:Skills:{index}");
    mockConfSection.Setup(s => s.Key).Returns(index.ToString());
    mockConfSection.Setup(s => s.GetChildren()).Returns(new List<IConfigurationSection> { mockConfSectionKey.Object, mockConfSectionId.Object });    
    
    //Add the skill object with merged attributes
    mockConfSections.Add(mockConfSection.Object);
}

// Add the Skill's list
var skillsMockSections = new Mock<IConfigurationSection>();
skillsMockSections.Setup(cfg => cfg.Path).Returns("Character:Skills");
skillsMockSections.Setup(cfg => cfg.Key).Returns("Skills");
skillsMockSections.Setup(cfg => cfg.GetChildren()).Returns(mockConfSections);

//Mock the whole section, for using GetSection() method withing SUT
configurationMock.Setup(cfg => cfg.GetSection("Character:Skills")).Returns(skillsMockSections.Object);

预期结果

运行原来的系统，我得到的是实例化的list及其各自的这是屏幕截图：

模拟结果

上面的代码，我只得到了实例化的列表，但所有属性return null。这是屏幕截图：

Answer 1

最后我重构了代码，去掉了整个 foreach 块，并用下面的代码替换了列表初始化 var mockConfSections = new List<IConfigurationSection>();，这样更简单、更清晰。

var fakeSkillSettings = skillsConfiguration.SelectMany(
    skill => new Dictionary<string, string> {
        { $"Character:Skills:{skillsConfiguration.IndexOf(skill)}:Key", skill.Key },
        { $"Character:Skills:{skillsConfiguration.IndexOf(skill)}:Id" , skill.Id  },
});

var configBuilder = new ConfigurationBuilder();
var mockConfSections = configBuilder.AddInMemoryCollection(fakeSkillSettings)
    .Build()
    .GetSection("Character:Skills")
    .GetChildren();

说明

由于之前的实现构建了一个带有模拟节点的配置树，因此需要为每个节点构建一个设置和 return，从而导致一个臃肿的解决方案。

根据文章 Keeping Configuration Settings in Memory, I projected the list with flattened Key/Id Dictionary using the LINQ SelectMany，然后构建内存配置，最后用“真实节点”模拟设置，得到一个模拟设置。

C# 为对象列表创建 Mock Configuration.GetSection(“Section:SubSection”)

C# Create Mock Configuration.GetSection(“Section:SubSection”) for objects list

c#

unit-testing

moq

mocking

xunit

Objective

之前的阅读

方法

代码

预期结果

模拟结果

说明