CliFx/CliFx.Tests/Utils/Extensions/AssertionExtensions.cs

using System;
using System.Collections.Generic;
using FluentAssertions;
using FluentAssertions.Execution;
using FluentAssertions.Primitives;

namespace CliFx.Tests.Utils.Extensions
{
    internal static class AssertionExtensions
    {
        public static void ConsistOfLines(
            this StringAssertions assertions,
            IEnumerable<string> lines)
        {
            var actualLines = assertions.Subject.Split(new[] {'\n', '\r'}, StringSplitOptions.RemoveEmptyEntries);
            actualLines.Should().Equal(lines);
        }

        public static void ConsistOfLines(
            this StringAssertions assertions,
            params string[] lines) =>
            assertions.ConsistOfLines((IEnumerable<string>) lines);

        public static AndConstraint<StringAssertions> ContainAllInOrder(
            this StringAssertions assertions,
            IEnumerable<string> values)
        {
            var lastIndex = 0;

            foreach (var value in values)
            {
                var index = assertions.Subject.IndexOf(value, lastIndex, StringComparison.Ordinal);

                if (index < 0)
                {
                    Execute.Assertion.FailWith(
                        $"Expected string '{assertions.Subject}' to contain '{value}' after position {lastIndex}."
                    );
                }

                lastIndex = index;
            }

            return new(assertions);
        }

        public static AndConstraint<StringAssertions> ContainAllInOrder(
            this StringAssertions assertions,
            params string[] values) =>
            assertions.ContainAllInOrder((IEnumerable<string>) values);
    }
}