DiffAssertExtensionsTest.cs

using System;
using System.Collections.Generic;
using AngleSharp.Diffing.Core;
using Moq;
using Shouldly;
using Xunit;
using Xunit.Sdk;

namespace Bunit
{
    public class DiffAssertExtensionsTest
    {
        [Fact(DisplayName = "ShouldHaveSingleChange throws when input is null")]
        public void Test001()
        {
            IReadOnlyList<IDiff>? diffs = null;
            Exception? exception = null;

            try
            {
                DiffAssertExtensions.ShouldHaveSingleChange(diffs!);
            }
            catch (Exception ex)
            {
                exception = ex;
            };

            exception.ShouldBeOfType<ArgumentNullException>();
        }

        [Theory(DisplayName = "ShouldHaveSingleChange throws when input length not exactly 1")]
        [MemberData(nameof(GetDiffLists))]
        public void Test002(IReadOnlyList<IDiff> diffs)
        {
            Exception? exception = null;

            try
            {
                diffs.ShouldHaveSingleChange();
            }
            catch (Exception ex)
            {
                exception = ex;
            };

            exception.ShouldBeOfType<EqualException>();
        }

        [Fact(DisplayName = "ShouldHaveSingleChange returns the single diff in input when there is only one")]
        public void Test003()
        {
            var input = new IDiff[] { Mock.Of<IDiff>() };

            var output = input.ShouldHaveSingleChange();

            output.ShouldBe(input[0]);
        }

        internal static IEnumerable<object[]> GetDiffLists()
        {
            yield return new object[] { Array.Empty<IDiff>() };
            yield return new object[]
            {
                new IDiff[]
                {
                    Mock.Of<IDiff>(),
                    Mock.Of<IDiff>(),
                }
            };
        }
    }
}