Saturday, September 26, 2009

Testing IIRF rules with MbUnit

If you're running IIS 6 like me, you know there aren't many options if you want extensionless URLs. I already had a custom URL rewriting engine in place with Windsor integration and stuff, but it couldn't handle extensionless URLs. The 404 solution seems kinda kludgy to me so after some pondering I decided to go with IIRF.

Ok, now let's see how do we test IIRF rules. IIRF is a regular Win32 DLL written in C, so there are no managed hook points that we can use from .Net. Fortunately, it comes with a testing tool called TestDriver, which is a standard .exe that takes a file with source and destination URLs and runs all source URLs against the rules, asserting that each result matches the destination.

All we need now is some glue code to integrate this to our regular tests so if any routes fail it also makes the whole build fail. I also want to see on my TeamCity build log exactly which route failed, and also be able to easily add new route tests. We can do all this with MbUnit's [Factory] and some stdout parsing. Here's the code:

[TestFixture]
public class IIRFTests {
    [Test]
    [Factory("IIRFTestFactory")]
    public void IIRFTest(string orig, string dest) {
        File.WriteAllText(@"SampleUrls.txt", string.Format("{0}\t{1}", orig, dest));
        var r = RunProcess(@"TestDriver.exe", @"-d .");
        if (r.ErrorLevel != 0) {
            var actual = Regex.Replace(r.Output.Replace("\r\n", " "), @".*actual\((.*)\).*", "$1");
            Assert.AreEqual(dest, actual);
        }
    }

    public IEnumerable<object[]> IIRFTestFactory() {
        yield return new object[] { "/questions/167586/visual-studio-database-project-designers", "/Question/Index.aspx?id=167586" };
        yield return new object[] { "/users/21239/mauricio-scheffer", "/User/Index.aspx?id=21239" };
    }

    public ProcessOutput RunProcess(string fileName, string arguments) {
        var p = Process.Start(new ProcessStartInfo(fileName, arguments) {
            CreateNoWindow = true,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
        });
        p.WaitForExit();
        return new ProcessOutput(p.ExitCode, p.StandardOutput.ReadToEnd() + p.StandardError.ReadToEnd());
    }

    public class ProcessOutput {
        public int ErrorLevel { get; private set; }
        public string Output { get; private set; }

        public ProcessOutput(int errorLevel, string output) {
            ErrorLevel = errorLevel;
            Output = output;
        }
    }
}

1 comment:

Jeff Brown said...

Nifty!

You might also find the methods of the Tasks class useful. For example, there's Tasks.StartProcessTask that will run a process of your choice, log the output and collect it for you. It also takes care of automatically killing the process at the end of the test if it is still running.