为什么在使用 Stub 时会收到 ExpectationViolationException？

Question

此测试使用 NUnit 2.5 和 Rhino.Mocks 3.5：

[TestFixture]
public class ExcelWorksheetColumnTests
{
        private const string _name = "F1";
        private const int _index = 0;

        private MockRepository _repo;


        [SetUp]
        public void SetUp(){_repo = new MockRepository();}


        private ExcelWorksheetColumn CreateColumnUsingFixtureFieldsButWith(IExcelWorksheet excelWorksheet)
        {
            return new ExcelWorksheetColumn(_name, _index, excelWorksheet);
        }

        [Test]
        public void When_SelectedShootColumnType_Is_Changed_Raises_SelectedShootColumnTypeChanged_Event()
        {
            var stubWorksheet = _repo.Stub<IExcelWorksheet>();

            ExcelWorksheetColumn column =
                CreateColumnUsingFixtureFieldsButWith(stubWorksheet);

            stubWorksheet
               .Stub(p => p.GetSelectedShootColumnType(column))
               .Return(ShootColumnType.Generic);

            _repo.ReplayAll();

            bool itHappened = false;

            column.SelectedShootColumnTypeChanged 
                += (s, e) => { itHappened = true; };

            column.SelectedShootColumnType = ShootColumnType.SubjectId;

            Assert.That(itHappened);
        }

        [TearDown]
        public void TearDown()
        {
            _repo.ReplayAll();
            _repo.VerifyAll();
        }
}

失败并显示此消息：

Rhino.Mocks.Exceptions.ExpectationViolationException ： IExcelWorksheet.SetSelectedShootColumnType( ClassPhotolink.Model.CreateSubjectList.ExcelWorksheetColumn, SubjectId);

预期 #0，实际 #1。

我认为存根用于返回值或忽略方法调用。为什么它试图验证调用

IExcelWorksheet.SetSelectedShootColumnType(
    IExcelWorksheetColumn column, 
    ShootColumnType type)

?

在 rhino mocks wiki 中，它说关于 Stub 扩展方法“请记住，默认情况下 Rhino Mocks 将忽略意外的方法调用。”

---

测试编辑。

删除 SetUp & TearDown 代码，仍然失败：

    [Test]
    public void When_SelectedShootColumnType_Is_Changed_Raises_SelectedShootColumnTypeChanged_Event()
    {
        var repo = new MockRepository();
        var stubWorksheet = repo.Stub<IExcelWorksheet>();

        ExcelWorksheetColumn column = CreateColumnUsingFixtureFieldsButWith(stubWorksheet);

        stubWorksheet
            .Stub(p => p.GetSelectedShootColumnType(column))
            .Return(ShootColumnType.Generic);

        repo.ReplayAll();

        bool itHappened = false;

        column.SelectedShootColumnTypeChanged += (s, e) => { itHappened = true; };

        column.SelectedShootColumnType = ShootColumnType.SubjectId;

        Assert.That(itHappened);
    }

但这如我所愿。

    [Test]
    public void When_SelectedShootColumnType_Is_Changed_Raises_SelectedShootColumnTypeChanged_Event()
    {
        var stubWorksheet = MockRepository.GenerateStub<IExcelWorksheet>();

        ExcelWorksheetColumn column = CreateColumnUsingFixtureFieldsButWith(stubWorksheet);

        stubWorksheet
            .Stub(p => p.GetSelectedShootColumnType(column))
            .Return(ShootColumnType.Generic);

        bool itHappened = false;

        column.SelectedShootColumnTypeChanged += (s, e) => { itHappened = true; };

        column.SelectedShootColumnType = ShootColumnType.SubjectId;

        Assert.That(itHappened);
    }

所以它似乎与 repo.Stub() 与 MockRepository.GenerateStub() 有关系；

Answer 1

使用Stub() 意味着您确实期待方法调用。 意外调用是对未设置期望的方法的调用。

更新

我现在想知道问题是否在于您使用不必要的设置、拆卸和记录/重放。

如果你这样写测试会发生什么：

[TestFixture]
public class ExcelWorksheetColumnTests
{
        private const string _name = "F1";
        private const int _index = 0;

        private ExcelWorksheetColumn CreateColumnUsingFixtureFieldsButWith(IExcelWorksheet excelWorksheet)
        {
            return new ExcelWorksheetColumn(_name, _index, excelWorksheet);
        }

        [Test]
        public void When_SelectedShootColumnType_Is_Changed_Raises_SelectedShootColumnTypeChanged_Event()
        {
            var stubWorksheet = MockRepository.Stub<IExcelWorksheet>();

            ExcelWorksheetColumn column =
                CreateColumnUsingFixtureFieldsButWith(stubWorksheet);

            stubWorksheet
               .Stub(p => p.GetSelectedShootColumnType(column))
               .Return(ShootColumnType.Generic);

            bool itHappened = false;

            column.SelectedShootColumnTypeChanged 
                += (s, e) => { itHappened = true; };

            column.SelectedShootColumnType = ShootColumnType.SubjectId;

            Assert.That(itHappened);
        }
}