如何跟踪 Entity Framework Core 事件以进行集成测试? [英] How to trace an Entity Framework Core event for integration testing?

问题描述

我们需要确保基于 EF Core 的代码已执行特定类型的数据库级操作(例如，any 命令执行或 any 事务提交).

We need to ensure that EF Core-based code has performed a specific kind of database-level operation under test (for example, any command execution or any transaction commit).

假设应该触发一个真实的数据库，并且我们不能通过 DbContext 模拟来隔离它.怎么看:

Let's suppose a real database should be triggered and we can't isolate it by DbContext mocking. How could it look:

[Fact]
public async Task Test()
{
    using (var context = new FooContext())
    {
        //context-related code to produce queries and commands
    }

    Assert.True(/* any context-related transaction has been committed */);
}

有可能吗?

推荐答案

EF Core 不提供自己的跟踪机制.但是，它记录了很多数据库交互事件.我们可以收集这些日志消息并检查它们的 EventId 以确定是否发生了特定操作.以下是 EF Core 使用的关系事件列表:

EF Core doesn't provide its own tracing mechanism. However, it logs a lot of database interaction events. We could gather these log messages and check their EventId to determine did a specific operation occur or not. Here is the list of relational events used by EF Core:

EF 核心 1.1.2:RelationalEventId 枚举.

EF Core 1.1.2: RelationalEventId enum.

EF Core 2.0.0 预览版 1:RelationalEventId 类(重大更改！).

EF Core 2.0.0 preview 1: RelationalEventId class (breaking change!).

我们需要做的就是创建一个伪造的记录器并将其传递给上下文:

All we need to do is create a fake logger and pass it to context:

[Fact]
public async Task TransactionCommit_Logger_ContainsEvent()
{
    var logger = new FakeLogger();

    var factoryMock = new Mock<ILoggerFactory>();
    factoryMock.Setup(f => f.CreateLogger(It.IsAny<string>()))
        .Returns(logger);

    using (var context = new FooContext(factoryMock.Object))
    {
        using (var transaction = await context.Database.BeginTransactionAsync())
        {
            transaction.Commit();
        }
    }

    Assert.True(logger.Events.Contains((int)RelationalEventId.CommittingTransaction));
}

FakeLogger 将记录的事件 ID 添加到 Events 列表.

FakeLogger adds a logged event id to the Events list.

public class FakeLogger : ILogger
{
    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception,
        Func<TState, Exception, string> formatter)
    {
        Events.Add(eventId.Id);
    }

    public List<int> Events { get; set; } = new List<int>();

    public bool IsEnabled(LogLevel logLevel) => true;

    public IDisposable BeginScope<TState>(TState state) => null;
}    

调用 UseLoggerFactory 将工厂实例附加到上下文:

Call UseLoggerFactory to attach a factory instance to a context:

public class FooContext : FooParentContext
{
    private readonly ILoggerFactory _loggerFactory;

    public FooContext() { }

    public FooContext(ILoggerFactory loggerFactory)
    {
        _loggerFactory = loggerFactory;
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        base.OnConfiguring(optionsBuilder);

        optionsBuilder.UseLoggerFactory(_loggerFactory);
    }
}

附言您可以更深入地分析日志消息，甚至是 EF 生成的 原始 SQL.

P.S. You could go even deeper and analyze log message or even raw SQL produced by EF.

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