Assert expression

Assertion.cs

[Conditional("DEBUG")]
public static void Assert(Expression<Func<bool>> assertion, string message, [CallerMemberName] string memberName = "", [CallerFilePath] string sourceFilePath = "", [CallerLineNumber] int sourceLineNumber = 0)
{
    bool condition = assertion.Compile()();
    if (!condition)
    {
        string errorMssage = string.Format("Failed assertion in {0} in file {1} line {2}: {3}", memberName, sourceFilePath, sourceLineNumber, assertion.Body.ToString());
        throw new AssertionException(message);
    }
}

Taken from: http://stackoverflow.com/questions/15147305/get-string-representing-the-expression-used-as-function-argument-in-c-sharp