Is this possible in C#?

Question

I have an extension method for testing so I can do this:

var steve = new Zombie();
steve.Mood.ShouldBe("I'm hungry for brains!");

The extension method:

public static void ShouldBe<T>(this T actual, T expected)
{
    Assert.That(actual, Is.EqualTo(expected));
}

This shows:

Expected: "I'm hungry for brains!"
But was:  "I want to shuffle aimlessly"

Is there any hack I can pull off to get the name of the property "BrainsConsumed" from within my extension method? Bonus points would be the instance variable and type Zombie.

UPDATE:

The new ShouldBe:

public static void ShouldBe<T>(this T actual, T expected)
{
    var frame = new StackTrace(true).GetFrame(1);
    var fileName = frame.GetFileName();
    var lineNumber = frame.GetFileLineNumber() - 1;
    var code = File.ReadAllLines(fileName)
        .ElementAt(lineNumber)
        .Trim().TrimEnd(';');

    var codeMessage = new Regex(@"(^.*)(\.\s*ShouldBe\s*\()([^\)]+)\)").Replace(code, @"$1 should be $3");

    var actualMessage = actual.ToString();
    if (actual is string)
        actualMessage = "\"" + actual + "\"";

    var message = string.Format(@"{0} but was {1}", codeMessage, actualMessage);

    Assert.That(actual, Is.EqualTo(expected), message);
}

and this prints out:

steve.Mood should be "I'm hungry for brains!" but was "I want to shuffle aimlessly"

Thanks everyone, esp. Matt Dotson, this is awesome. BTW don't feed the silky trolls people.

Answer 1

You can get the code if it's a debug build by using some of the diagnostics classes. Given that this is for unit tests, DEBUG is probably reasonable.

public static void ShouldBe<T>(this T actual, T expected)

{

var frame = new StackTrace(true).GetFrame(1);
var fileName = frame.GetFileName();
var lineNumber = frame.GetFileLineNumber() - 1;

string code = File.ReadLines(fileName).ElementAt(lineNumber).Trim();

Debug.Assert(actual.Equals(expected), code);

}

For your example, code = "steve.BrainsConsumed.ShouldBe(0);"

Obviously you should add some error checking to this code, and you could probably make it faster by not reading all the lines in the file.