在单元测试中模拟 IHttpContextAccessor

问题描述

我有一种使用 IHttpContextAccessor

public class HeaderConfiguration : IHeaderConfiguration
{
    public HeaderConfiguration()
    {

    }

    public string GetTenantId(IHttpContextAccessor httpContextAccessor)
    {
        return httpContextAccessor.HttpContext.Request.Headers["Tenant-ID"].ToString();
    }
}

我正在测试 GetBookByBookId 方法

假设该方法如下所示:

public class Book
{
    private readonly IHttpContextAccessor _httpContextAccessor;
    private IHeaderConfiguration _headerConfiguration;
    private string _tenantID;

    public Book(IHeaderConfiguration headerConfiguration, IHttpContextAccessor httpContextAccessor){
        var headerConfig = new HeaderConfiguration();
        _httpContextAccessor = httpContextAccessor;
        _tenantID = headerConfig.GetTenantId(_httpContextAccessor);
    }

    public Task<List<BookModel>> GetBookByBookId(string id){
        //do something with the _tenantId
        //...
    }
}

这是我对 GetBookByBookId 方法的单元测试

Here's my unit test for GetBookByBookId method

[Fact]
public void test_GetBookByBookId()
{
    //Arrange

    //Mock IHttpContextAccessor
    var mockHttpContextAccessor = new Mock<IHttpContextAccessor>();

    mockHttpContextAccessor.Setup(req => req.HttpContext.Request.Headers["Tenant-ID"].ToString()).Returns(It.IsAny<string>());
    //Mock HeaderConfiguration
    var mockHeaderConfiguration = new Mock<IHeaderConfiguration>();
    mockHeaderConfiguration.Setup(x => x.GetTenantId(mockHttpContextAccessor.Object)).Returns(It.IsAny<string>());

    var book = new Book( mockHttpContextAccessor.Object, mockHeaderConfiguration.Object);

    var bookId = "100";

    //Act
    var result = book.GetBookByBookId(bookId);

    //Assert
    result.Result.Should().NotBeNull().And.
        BeOfType<List<BookModel>>();
}

但是对于这一行:

mockHttpContextAccessor.Setup(req => req.HttpContext.Request.Headers["Tenant-ID"].ToString()).Returns(It.IsAny<string>());

它说

System.NotSupportedException: '要模拟的类型必须是接口或抽象或非密封类.'

我想知道用标头值模拟 IHttpContextAccessor 的正确方法是什么?

I was wondering what's the proper way to mock IHttpContextAccessor with header value?

推荐答案

您可以使用 DefaultHttpContext 作为 IHttpContextAccessor.HttpContext 的支持.让您不必设置太多东西

You can use the DefaultHttpContext as a backing for the IHttpContextAccessor.HttpContext. Saves you having to set-up too many things

接下来你不能使用 It.IsAny() 作为 Returns 结果.它们旨在单独用于设置表达式.

Next you cannot use It.IsAny<string>() as a Returns result. They were meant to be used in the set up expressions alone.

检查重构

[Fact]
public async Task test_GetBookByBookId() {
    //Arrange

    //Mock IHttpContextAccessor
    var mockHttpContextAccessor = new Mock<IHttpContextAccessor>();
    var context = new DefaultHttpContext();
    var fakeTenantId = "abcd";
    context.Request.Headers["Tenant-ID"] = fakeTenantId;
    mockHttpContextAccessor.Setup(_ => _.HttpContext).Returns(context);
    //Mock HeaderConfiguration
    var mockHeaderConfiguration = new Mock<IHeaderConfiguration>();
    mockHeaderConfiguration
        .Setup(_ => _.GetTenantId(It.IsAny<IHttpContextAccessor>()))
        .Returns(fakeTenantId);

    var book = new Book(mockHttpContextAccessor.Object, mockHeaderConfiguration.Object);

    var bookId = "100";

    //Act
    var result = await book.GetBookByBookId(bookId);

    //Assert
    result.Should().NotBeNull().And.
        BeOfType<List<BookModel>>();
}

被测类也可能存在问题，因为它在实际显式注入时手动初始化 HeaderConfiguration.

There may also be an issue with the Class Under Test as it is manually initializing the HeaderConfiguration when it should actually be explicitly injected.

public Book(IHeaderConfiguration headerConfiguration, IHttpContextAccessor httpContextAccessor) {
    _httpContextAccessor = httpContextAccessor;
    _tenantID = headerConfiguration.GetTenantId(_httpContextAccessor);
}

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