Asserts that assertionExpression does not throw an exception.
public static void DoesNotThrow(Expression<Action> assertionExpression)
Asserts that assertionExpression does not throw an exception and allows chaining further asserts on the current value.
public static Task<Assertable<T>> DoesNotThrow<T>(this Task<Assertable<T>> source, 
    Expression<Action<T>> assertionExpression)
    where T : class