在处理List＆lt; T＆gt;时，重构单元测试的挑战是可维护和可读的。对象
在“单元测试的艺术”一书中，它谈到了想要创建可维护和可读的单元测试。在第204页左右，它提到应该尝试在一次测试中避免多个断言，并且可能使用重写的Equals方法比较对象。当我们只有一个对象来比较预期结果和实际结果时，这很有效。但是，如果我们有所述对象的列表（或集合），该怎么办？
考虑下面的测试。我有多个断言。实际上，有两个独立的循环调用断言。在这种情况下，我将最终得到5个断言。 2检查另一个列表中存在的内容，反之亦然。第五个比较列表中的元素数量。
如果有人有改进这项测试的建议，我会全力以赴。我现在正在使用MSTest，尽管我用NUnits替换了MSTest的Assert用于流畅的API（Assert.That）。
当前重构代码：
[TestMethod]
#if !NUNIT
[HostType("Moles")]
#else
[Moled]
#endif
public void LoadCSVBillOfMaterials_WithCorrectCSVFile_ReturnsListOfCSVBillOfMaterialsThatMatchesInput()
{
//arrange object(s)
var filePath = "Path Does Not Matter Because of Mole in File object";
string[] csvDataCorrectlyFormatted = { "1000, 1, Alt 1, , TBD, 1, 10.0, Notes, , Description, 2.50, ,A",
"1001, 1, Alt 2, , TBD, 1, 10.0, Notes, , Description, 2.50, ,A" };
var materialsExpected = new List<CSVMaterial>();
materialsExpected.Add(new CSVMaterial("1000", 1, "Alt 1", "TBD", 1m, 10.0m, "Notes", "Description", 2.50m,"A"));
materialsExpected.Add(new CSVMaterial("1001", 1, "Alt 2", "TBD", 1m, 10.0m, "Notes", "Description", 2.50m,"A"));
//by-pass actually hitting the file system and use in-memory representation of CSV file
MFile.ReadAllLinesString = s => csvDataCorrectlyFormatted;
//act on object(s)
var materialsActual = modCSVImport.LoadCSVBillOfMaterials(filePath);
//assert something happended
Assert.That(materialsActual.Count,Is.EqualTo(materialsExpected.Count));
materialsExpected.ForEach((anExpectedMaterial) => Assert.That(materialsActual.Contains(anExpectedMaterial)));
materialsActual.ForEach((anActualMaterial) => Assert.That(materialsExpected.Contains(anActualMaterial)));
}
...
//1st element
Assert.AreEqual("1000", materials[0].PartNumber);
Assert.AreEqual(1, materials[0].SequentialItemNumber);
Assert.AreEqual("Alt 1", materials[0].AltPartNumber);
Assert.AreEqual("TBD", materials[0].VendorCode);
Assert.AreEqual(1m, materials[0].Quantity);
Assert.AreEqual(10.0m, materials[0].PartWeight);
Assert.AreEqual("Notes", materials[0].PartNotes);
Assert.AreEqual("Description", materials[0].PartDescription);
Assert.AreEqual(2.50m, materials[0].UnitCost);
Assert.AreEqual("A", materials[1].Revision);
//2nd element
Assert.AreEqual("1001", materials[1].PartNumber);
Assert.AreEqual(1, materials[1].SequentialItemNumber);
Assert.AreEqual("Alt 2", materials[1].AltPartNumber);
Assert.AreEqual("TBD", materials[1].VendorCode);
Assert.AreEqual(1m, materials[1].Quantity);
Assert.AreEqual(10.0m, materials[1].PartWeight);
Assert.AreEqual("Notes", materials[1].PartNotes);
Assert.AreEqual("Description", materials[1].PartDescription);
Assert.AreEqual(2.50m, materials[1].UnitCost);
Assert.AreEqual("A", materials[1].Revision);
}
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的类型，这使得测试比你的第二种形式简单得多。但是在你的第一次测试中，它看起来你真的只想断言结果集合等于预期的集合。我认为这在逻辑上是一个断言 - 只是目前你正在执行多个迷你断言来测试它。 一些单元测试框架有测试两个集合是否相等的方法 - 如果你使用的集合没有，你可以轻松编写一个。我最近在“重新实现LINQ to Objects”博客系列中做到了这一点，因为虽然NUnit提供了一个辅助方法，但它的诊断并不是非常有用。基本上，我对MoreLINQ的代码进行了非常轻微的重构。锑寝粒
方法并添加了一个更有用的断言消息。所以我认为这有助于代码的可读性和可维护性。它还使单元测试值得信赖（由于有用的诊断消息）。 而Jon，感谢关于逻辑工作单元的思考。我重构的代码与前一次迭代的内容大致相同。两者仍然测试一个逻辑的东西。另外，我将不得不研究MoreLINQ的内容。如果它出现在你的C＃InDepth第2版书中，那么当我从Manning购买MEAP版本时，我会遇到它。谢谢你的帮助。public void LoadCSVBillOfMaterials_WithCorrectCSVFile_ReturnsListOfCSVBillOfMaterialsThatMatchesInput() { //arrange object(s) var filePath = "Path Does Not Matter Because of Mole in File object"; string[] csvDataCorrectlyFormatted = { "1000, 1, Alt 1, , TBD, 1, 10.0, Notes, , Description, 2.50, ,A", "1001, 1, Alt 2, , TBD, 1, 10.0, Notes, , Description, 2.50, ,A" }; var materialsExpected = new List<CSVMaterial>(); materialsExpected.Add(new CSVMaterial("1001", 1, "Alt 1", "TBD", 1m, 10.0m, "Notes", "Description", 2.50m,"A")); materialsExpected.Add(new CSVMaterial("1001", 1, "Alt 2", "TBD", 1m, 10.0m, "Notes", "Description", 2.50m,"A")); //by-pass actually hitting the file system and use in-memory representation of CSV file MFile.ReadAllLinesString = s => csvDataCorrectlyFormatted; //act on object(s) var materialsActual = modCSVImport.LoadCSVBillOfMaterials(filePath); //assert something happended //Setup message for failed asserts var assertMessage = new StringBuilder(); assertMessage.AppendLine("Actual Materials:"); materialsActual.ForEach((m) => assertMessage.AppendLine(m.ToString())); assertMessage.AppendLine("Expected Materials:"); materialsExpected.ForEach((m) => assertMessage.AppendLine(m.ToString())); Assert.That(materialsActual, Is.EquivalentTo(materialsExpected),assertMessage.ToString()); }