我如何重寫此foreach使其成為以前的Linq表達式的一部分？

Question

我正在用自定義屬性， SpecificationAttribute和VerificationAttribute裝飾我的MSTest測試，以后將它們用於生成html測試規范報告。

屬性如下所示：

[AttributeUsage(AttributeTargets.Method, AllowMultiple = true)]
public class SpecificationAttribute : Attribute
{
    public SpecificationAttribute(int step, string text)
    {
        Step = step;
        Text = text;
    }

    public int Step { get; set; }

    public string Text { get; set; }
}

我編寫了一個測試，該測試斷言測試方法在使用屬性時必須具有唯一的步驟。 例如，以下用法未能通過我的測試，因為它應該：

[Specification(1, "Click Button)]
[Verification(1, "Verify popup")]
[Specification(1, "Click close")]
[Verification(2, "Verify popup disappears")]

我的測試看起來像這樣：

[TestMethod]
public void TestForNoDuplicateStepsOnMethod()
{
    var specificationMethods = Assembly.GetExecutingAssembly().GetTypes()
        .Where(type =>
            type.GetCustomAttribute<CompilerGeneratedAttribute>() == null &&
                type.GetCustomAttribute<TestClassAttribute>() != null)
        .SelectMany(type => type.GetMethods())
        .Where(methodInfo =>
            methodInfo.GetCustomAttribute<TestMethodAttribute>() != null &&
            methodInfo.GetCustomAttributes<SpecificationAttribute>().Any())
        .ToArray();

    foreach (var method in specificationMethods)
    {
        var specificationAttributes = method.GetCustomAttributes<SpecificationAttribute>();

        var duplicates = specificationAttributes.GroupBy(s => s.Step).Where(grp => grp.Count() > 1).SelectMany(x => x).ToList();

        if (duplicates.Any())
        {
            var initialMessage = $@"{Environment.NewLine}{method.DeclaringType}.{method.Name} contains several SpecificationAttribute with the same step number." + Environment.NewLine + Environment.NewLine;

            var message = duplicates.Aggregate(initialMessage, (s, attribute) => s + attribute.Step + " " + attribute.Text + Environment.NewLine);

            Assert.Fail(message);
        }
    }
}

我想重寫最后一部分，使其成為Linq查詢的一部分。 這可能嗎？ 另外，我當前的測試僅輸出一種失敗的方法。 如果Linq查詢可以包括在唯一步驟號上具有失敗條件的所有方法，那將是可取的。

Answer 1

如果您不需要對var SpecificationMethods進行更多操作，則可以嘗試以下操作：

 [TestMethod]
    public void TestForNoDuplicateStepsOnMethod()
    {
        Assembly.GetExecutingAssembly().GetTypes()
            .Where(type =>
                type.GetCustomAttribute<CompilerGeneratedAttribute>() == null &&
                    type.GetCustomAttribute<TestClassAttribute>() != null)
            .SelectMany(type => type.GetMethods())
            .Where(methodInfo =>
                methodInfo.GetCustomAttribute<TestMethodAttribute>() != null &&
                methodInfo.GetCustomAttributes<SpecificationAttribute>().Any())
            .ToList().ForEach (method=> 
        {
            var specificationAttributes = method.GetCustomAttributes<SpecificationAttribute>();

            var duplicates = specificationAttributes.GroupBy(s => s.Step).Where(grp => grp.Count() > 1).SelectMany(x => x).ToList();

            if (duplicates.Any())
            {
                var initialMessage = $@"{Environment.NewLine}{method.DeclaringType}.{method.Name} contains several SpecificationAttribute with the same step number." + Environment.NewLine + Environment.NewLine;

                var message = duplicates.Aggregate(initialMessage, (s, attribute) => s + attribute.Step + " " + attribute.Text + Environment.NewLine);

                Assert.Fail(message);
            }
    }
  }
}

Answer 2

（經過編輯以通過積極的測試解決該問題）嘗試此操作，但是恕我直言，它很難閱讀。

[TestMethod]
public void TestForNoDuplicateStepsOnMethod()
{
    var errors = Assembly.GetExecutingAssembly().GetTypes()
        .Where(type =>
            type.GetCustomAttribute<CompilerGeneratedAttribute>() == null &&
                type.GetCustomAttribute<TestClassAttribute>() != null)
        .SelectMany(type => type.GetMethods())
        .Where(methodInfo =>
            methodInfo.GetCustomAttribute<TestMethodAttribute>() != null &&
            methodInfo.GetCustomAttributes<SpecificationAttribute>().Any())
        .Select(method =>
            method.GetCustomAttributes<SpecificationAttribute>()
        .GroupBy(s => s.Step)
            .Where(grp => grp.Count() > 1)
            .Select(x => x.Aggregate(
                $@"{Environment.NewLine}{method.DeclaringType}.{method.Name} contains several SpecificationAttribute with the same step number." 
                + Environment.NewLine,
                (s, attribute) => s + attribute.Step + " " + attribute.Text + Environment.NewLine))
                .Aggregate("", (s, message) => s + message))
            .Aggregate("", (s, message) => s + message);
        Assert.AreEqual("", errors);
}