c# - 对于 BDD/TDD 这种风格的改进有什么建议吗？

Question

我正在尝试使用我们的单元测试规范进行设置

在场景 Y 中发生行为 X 时 SUT 的规范 鉴于这件事 还有这件事 当我做 X... 那么它应该做... 它也应该做...

我将 GivenThat 的每个步骤都包装在 Actions 中......是否有任何反馈，无论与 Actions 分开是好是坏，还是让 GivenThat 更清晰的更好方法？

        /// <summary>
        /// Given a product is setup for injection
        ///     And Product Image Factory Is Stubbed();
        ///     And Product Size Is Stubbed();
        ///     And Drawing Scale Is Stubbed();
        ///     And Product Type Is Stubbed();
        /// </summary>
        protected override void GivenThat()
        {
            base.GivenThat();

            Action givenThatAProductIsSetupforInjection = () =>
              {
                  var randomGenerator = new RandomGenerator();

                  this.Position = randomGenerator.Generate<Point>();

                  this.Product = new Diffuser
                                     {
                                         Size =
                                             new RectangularProductSize(
                                             2.Inches()),
                                         Position = this.Position,
                                         ProductType =
                                             Dep<IProductType>()
                                     };
              };

            Action andProductImageFactoryIsStubbed = () => Dep<IProductBitmapImageFactory>().Stub(f => f.GetInstance(Dep<IProductType>())).Return(ExpectedBitmapImage);

            Action andProductSizeIsStubbed = () =>
                 {
                     Stub<IDisplacementProduct, IProductSize>(p => p.Size);

                     var productBounds = new ProductBounds(Width.Feet(), Height.Feet());

                     Dep<IProductSize>().Stub(s => s.Bounds).Return(productBounds);
                 };

            Action andDrawingScaleIsStubbed = () => Dep<IDrawingScale>().Stub(s => s.PixelsPerFoot).Return(PixelsPerFoot);

            Action andProductTypeIsStubbed = () => Stub<IDisplacementProduct, IProductType>(p => p.ProductType);

            givenThatAProductIsSetupforInjection();
            andProductImageFactoryIsStubbed();
            andProductSizeIsStubbed();
            andDrawingScaleIsStubbed();
            andProductTypeIsStubbed();
        }

Answer 1

将它们放在不同的方法中，以便您可以将它们组合在其他给定的方法中。此外，使用下划线代替空格(而不是驼峰式)。此外，创建一个方法 Given_that 接受 Action 委托(delegate)的参数。

protected void Given_that(params Action[] preconditions)
{
    foreach (var action in preconditions)
    {
        action();
    }
}

...

protected void a_product_is_set_up_for_injection()
{
    ...
}

protected void product_image_factory_is_stubbed()
{
    ...
}

etc...

...

Given_that(a_product_is_set_up_for_injection,
           product_image_factory_is_stubbed,
           product_size_is_stubbed,
           drawing_scale_is_stubbed,
           product_type_is_stubbed);

话虽这么说，我认为你的先决条件的命名不是 BDD。它们本质上是非常技术性的，并不表示业务需求。如果您要告诉非程序员您正在测试什么，您可能不会说“该产品已 stub 用于注入(inject)”。你更有可能说

Given a displacement product
    that is a two inch rectangular diffuser
    that has a random position
    that has a bitmap
    that has a size bounded by feet
    that has the expected pixels per foot

现在您可以编写您的“给定”方法，几乎​​没有重复:

protected [the type of your test class] Given(params Action given)
{
    given();
    return this;
}

protected void That(params Action[] preconditions)
{
    foreach (var precondition in preconditions)
    {
        precondition();
    }
}

Given(a_displacement_product)
    .That(is_a_two_inch_rectangular_diffuser,
          has_a_random_position,
          has_a_bitmap,
          has_a_size_bounded_by_feet,
          has_the_expected_pixels_per_foot);