单元测试 – 如何对具有复杂输入输出的方法进行单元测试

[TestFixture]
    public class XmlParserTest
    {
        [Test,ExpectedException(typeof(XmlException))]
        public void FailIfXmlIsNotWellFormed()
        {
            Parse("<doc>");
        }

        [Test]
        public void ParseShortTag()
        {
            var doc = Parse("<doc/>");

            Assert.That(doc.DocumentElement.Name,Is.EqualTo("doc"));
        }

        [Test]
        public void ParseFullTag()
        {
            var doc = Parse("<doc></doc>");

            Assert.That(doc.DocumentElement.Name,Is.EqualTo("doc"));
        }

        [Test]
        public void ParseInnerText()
        {
            var doc = Parse("<doc>Text 1</doc>");

            Assert.That(doc.DocumentElement.InnerText,Is.EqualTo("Text 1"));
        }

        [Test]
        public void AttributesAreEmptyifThereAreNoAttributes()
        {
            var doc = Parse("<doc></doc>");

            Assert.That(doc.DocumentElement.Attributes,Has.Count(0));
        }

        [Test]
        public void ParseAttribute()
        {
            var doc = Parse("<doc attribute11='attribute 11 value'></doc>");

            Assert.That(doc.DocumentElement.Attributes[0].Name,Is.EqualTo("attribute11"));
            Assert.That(doc.DocumentElement.Attributes[0].Value,Is.EqualTo("attribute 11 value"));
        }

        [Test]
        public void ChildNodesInnerTextAtFirstLevel()
        {
            var doc = Parse(@"<root>
              <child1>Text 1</child1>
              <child2>Text 2</child2>
            </root>");

            Assert.That(doc.DocumentElement.ChildNodes,Has.Count(2));
            Assert.That(doc.DocumentElement.ChildNodes[0].InnerText,Is.EqualTo("Text 1"));
            Assert.That(doc.DocumentElement.ChildNodes[1].InnerText,Is.EqualTo("Text 2"));
        }

        // More tests 
        .....

        private XmlDocument Parse(string xml)
        {
            var doc = new XmlDocument();

            doc.LoadXml(xml);

            return doc;
        }
    }

这种方法有很多优点：

>容易缺陷的位置 – 如果
属性有问题
解析,然后只测试
属性将失败.
>小测试总是更容易理解

UPD：看看Gerard Meszaros(xUnit测试模式的作者书)关于主题的说法：xunitpatterns

One possibly contentious aspect of Verify One Condition per Test is what we mean by “one condition”. Some test drivers insist on one assertion per test. This insistence may be based on using a Testcase Class per Fixture organization of the Test Methods and naming each test based on what the one assertion is verifying(E.g. AwaitingApprovalFlight.validApproverRequestShouldBeApproved.). Having one assertion per test makes such naming very easy but it does lead to many more test methods if we have to assert on many output fields. Of course,we can often comply with this interpretation by extracting a Custom Assertion (page X) or Verification Method (see Custom Assertion) that allows us to reduce the multiple assertion method calls into one. Sometimes that makes the test more readable but when it doesn’t,I wouldn’t be too dogmatic about insisting on a single assertion.