2008-08-31 assert-that

# Assert That!
# Author: Mikael Lundin
# Link: http://blog.mikaellundin.name/2008/08/31/assert-that.html

AssertNonNull.cs

public static void AssertNonNull(this object argument, string message)
{
    argument.AssertThat(arg => arg != null, message);
}

public static void AssertNonNullOrEmpty(this string argument, string message)
{
    argument.AssertThat(s => !string.IsNullOrEmpty(s), message);
}

AssertThat.cs

public static void AssertThat(this T argument, Predicate<t> condition, string message)
{
        if (!condition(argument))
            throw new AssertException(message);
}

Repeat.cs

public string Repeat(string arg, int count)
{
    arg.AssertThat(s => s != null,
        "Repeat was called with arg == null");

    count.AssertThat(i => i > -1,
        "Repeat was called with count = (negative number)");

    return count == 0 ? string.Empty : arg + Repeat(arg, count--);
}