Add Assert.Throws<TEx>( Func<object> ) for properties testing

[Yuri Astrakhan]

Sometimes an object is in a state that causes reading its properties to throw exception. For example, an object might be disposed, and will throw InvalidOperationException().

To test for such behavior, one would write

    var obj = CreateDisposedObject();
#pragma warning disable 168
    // Assuming Name cannot be accessed after disposing
    Assert.Throws<InvalidOperationException>(() => { var v = obj.Name; });
#pragma warning restore 168

Having pragmas and a temp variable is clearly inconvenient, and instead can be remedied with this overload:

    public static T Throws<T>(Func<object> code) where T : Exception
    {
        return Assert.Throws<T>(() => { var v = code(); });
    }

As a result, our code can now be written as:

    var obj = CreateDisposedObject();
    Assert.Throws<InvalidOperationException>(() => obj.Name);

Much more concise and self evident.

Thank you!

[Vitalii Maklai (vmcl)]

I would prefer something like:

public static TException Throws<TException, T>(Func<T> action)
    where TException : Exception
{
    return Assert.Throws<TException>(() => { var v = action(); });
}