模拟实体框架核心上下文 [英] Mocking Entity Framework Core context

问题描述

我尝试测试我的应用，所以我需要模拟我的EF上下文.

I try to test my app so I need to mock my EF context.

我的代码似乎还可以，但是我有以下异常:

My code seems to be ok, but I have following exception:

"System.ArgumentNullException:值不能为null.参数名称: 来源"

"System.ArgumentNullException : Value cannot be null. Parameter name: source"

这是我的测试方法:

  var options = new DbContextOptionsBuilder<ProductContext>().Options;
    var settings = new SqlSettings
    {
        InMemory = true
    };

    var context = new Mock<ProductContext>(options, settings);
    var mockTreeService = new TreeService(context.Object);
    await mockTreeService.CreateTreeAsync("Testing tree", Guid.NewGuid());

    context.Verify(x => x.AddAsync(It.IsAny<Tree>(), CancellationToken.None), Times.Once);

在执行这段代码期间，似乎抛出了此异常

It looks like that this exception is thrown during executing this piece of code

            var tree = await _context.Trees
                .Include(x => x.Translation)
                .FirstOrDefaultAsync(x => x.Translation.Pl == name);

它来自我正在测试的服务

It comes from my service which I'm testing

推荐答案

我认为这是由于没有设置连接字符串.坦白说，要完全模拟DbContext有点困难，这就是EF Core团队提供内存中实现的原因.出于测试目的，这要容易得多.只需将您的options初始化更改为:

I think this is due to not having a connection string set. Frankly, it's a bit difficult to fully mock out DbContext, which is why the EF Core team has provided an in-memory implementation. This is far easier to work with for testing purposes. Just change your options initialization to:

var options = new DbContextOptionsBuilder<ProductContext>()
                  .UseInMemoryDatabase(Guid.NewGuid().ToString())
                  .Options;

然后，您需要用测试数据填充数据库.然后，您可以运行其余测试.

Afterwards, you'll need to populate the database with your test data. Then, you can run the rest of your test.

注意:如果您使用的是内存数据库，则不再需要模拟上下文，因此可以删除该部分代码.内存数据库本质上是一个模拟.

这篇关于模拟实体框架核心上下文的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！