[英]Unit testing exception property
I have exception 我有例外
class SyntaxError : Exception {
public SyntaxError(int l) {
line = l;
}
public int line;
}
I'm using unit tests to test class Parser which on specific input should throw exception above. 我正在使用单元测试来测试类Parser,在特定输入上应该抛出异常。 I'm using code like this:
我正在使用这样的代码:
[TestMethod]
[ExpectedException(typeof(Parser.SyntaxError))]
public void eolSyntaxError()
{
parser.reader = new StringReader("; alfa\n; beta\n\n\n\na");
parser.eol();
}
Is there any smart simple way to check if SyntaxError.line == 1
? 是否有任何智能简单的方法来检查
SyntaxError.line == 1
?
Best I come up with is: 我想出的最好的是:
[TestMethod]
public void eolSyntaxError()
{
try {
parser.reader = new StringReader("; alfa\n; beta\n\n\n\na");
parser.eol();
Assert.Fail();
} catch (SyntaxError e) {
Assert.AreEqual(1, e.line);
}
}
I don't like it very much, is there better way? 我不太喜欢它,有更好的方法吗?
Consider using FluentAssertions . 考虑使用FluentAssertions 。 Your test will then look like this:
您的测试将如下所示:
[TestMethod]
public void eolSyntaxError()
{
parser.reader = new StringReader("; alfa\n; beta\n\n\n\na");
Action parseEol = () => parser.eol();
parseEol
.ShouldThrow<SyntaxError>()
.And.line.Should().Be(1);
}
Otherwise, your approach is pretty much as good as it gets. 否则,你的方法几乎和它一样好。
You could write a method similar to the one in NUnit 您可以编写类似于NUnit中的方法
public T Throws<T>(Action code) where T : Exception
{
Exception coughtException = null;
try
{
code();
}
catch (Exception ex)
{
coughtException = ex;
}
Assert.IsNotNull(coughtException, "Test code didn't throw exception");
Assert.AreEqual(coughtException.GetType(), typeof(T), "Test code didn't throw same type exception");
return (T)coughtException;
}
And then you can use it in your test method 然后你可以在你的测试方法中使用它
Parser.SyntaxError exception = Throws<Parser.SyntaxError>(() => parser.eol());
Assert.AreEqual(1, exception.line);
As per my comment, if the line at which you encounter the syntax error is relevant, then include it in your custom exception class, like so. 根据我的评论,如果您遇到语法错误的行是相关的,那么将它包含在您的自定义异常类中,就像这样。
public class SyntaxError : Exception
{
public SyntaxError(int atLine)
{
AtLine = atLine;
}
public int AtLine { get; private set; }
}
Then it's easy to test. 然后它很容易测试。
EDIT - After having read the question (!) here's a simple additional Assert method which will tidy up your exception assertions. 编辑 - 在阅读了问题(!)后,这是一个简单的附加Assert方法,它将整理你的异常断言。
public static class xAssert
{
public static TException Throws<TException>(Action a) where TException : Exception
{
try
{
a();
}
catch (Exception ex)
{
var throws = ex as TException;
if (throws != null)
return throws;
}
Assert.Fail();
return default(TException);
}
}
Usage as follows... 用法如下......
public class Subject
{
public void ThrowMyException(int someState)
{
throw new MyException(someState);
}
public void ThrowSomeOtherException()
{
throw new InvalidOperationException();
}
}
public class MyException : Exception
{
public int SomeState { get; private set; }
public MyException(int someState)
{
SomeState = someState;
}
}
[TestClass]
public class UnitTest1
{
[TestMethod]
public void TestMethod1()
{
var subject = new Subject();
var exceptionThrown = xAssert.Throws<MyException>(() => { subject.ThrowMyException(123); });
Assert.AreEqual(123, exceptionThrown.SomeState);
}
}
I am not aware of an out of the box solution for this, but I have seen the concept of expectations which work like this: 我不知道为此提供开箱即用的解决方案,但我已经看到了期望的概念,它的工作原理如下:
[TestMethod]
public void EolSyntaxError()
{
Expectations.Expect<(SyntaxError>(
() =>
{
parser.reader = new StringReader("; alfa\n; beta\n\n\n\na");
parser.eol();
},
e =>
{
Assert.AreEqual(1, e.line);
});
}
Expectations needs to be implemented. 期望需要实施。 I reckon there will be libraries out there which already do this.
我估计那里会有图书馆已经做到了这一点。 Anyhow, the
Expect
method in Expectations
could look like this: 无论如何,
Expectations
的Expect
方法看起来像这样:
public static void Expect<TExpectedException>(
System.Action action,
System.Action<TExpectedException> assertion) where TExpectedException : Exception
{
if (action == null) { throw new ArgumentNullException("action"); }
try
{
action.Invoke();
Assert.Fail(string.Format("{0} expected to be thrown", typeof(TExpectedException).Name));
}
catch (TExpectedException e)
{
assertion.Invoke(e);
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.