/test/NRopes.Tests/RopeTestsBase.cs

namespace NRopes.Tests {

    using System;

    using System.Collections.Generic;

    using FluentAssertions;

    using Xunit;



    public abstract class RopeTestsBase {

        protected abstract IEnumerable<Rope> TargetRopes { get; }



        [Fact]

        public void SubstringShouldThrowExceptionsForInvalidParameters() {

            foreach (var rope in TargetRopes) {

                rope.Invoking(r => r.Substring(-1))

                    .ShouldThrow<ArgumentOutOfRangeException>().And

                    .ParamName.Should().Be("startIndex");



                rope.Invoking(r => r.Substring(r.Length + 1))

                    .ShouldThrow<ArgumentOutOfRangeException>().And

                    .ParamName.Should().Be("startIndex");



                rope.Invoking(r => r.Substring(0, -1))

                    .ShouldThrow<ArgumentOutOfRangeException>().And

                    .ParamName.Should().Be("length");



                rope.Invoking(r => r.Substring(0, r.Length + 1))

                    .ShouldThrow<ArgumentOutOfRangeException>().And

                    .ParamName.Should().Be("length");

            }

        }



        [Fact]

        public void SubstringShouldReturnSelfForZeroStartIndexAndFullLength() {

            foreach (var rope in TargetRopes) {

                if (rope.Length > 0) {

                    rope.Substring(0, rope.Length).Should().BeSameAs(rope);

                }

            }

        }



        [Fact]

        public void SubstringShouldReturnEmptyForZeroLength() {

            foreach (var rope in TargetRopes) {

                rope.Substring(rope.Length, 0).Should().BeSameAs(Rope.Empty);

            }

        }

    }

}