Контейнер с наибольшим объемом

Solution.cs

using System;

namespace ConsoleApp1
{
    public static class Solution
    {
        public static int FindMaxArea(int[] heights)
        {
            var leftIndex = 0;
            var rightIndex = heights.Length - 1;
            var maxArea = 0;
            while (leftIndex < rightIndex)
            {
                var width = rightIndex - leftIndex;
                var height = Math.Min(heights[leftIndex], heights[rightIndex]);
                var area = width * height;
                maxArea = Math.Max(area, maxArea);
                if (heights[leftIndex] < heights[rightIndex])
                    leftIndex++;
                else
                    rightIndex--;
            }

            return maxArea;
        }
    }
}

SolutionTests.cs

using System;
using ConsoleApp1;
using FluentAssertions;
using NUnit.Framework;

namespace Tests
{
    public class SolutionTests
    {

        [Test]
        public void FindMaxArea_ShouldReturn0_WhenOnlyOneHeight()
        {
            var heights = new [] {4};
            var expected = 0;

            var actual = Solution.FindMaxArea(heights);

            actual.Should().Be(expected);
        }

        [Test]
        public void FindMaxArea_ShouldReturn0_WhenNoHeights()
        {
            var heights = Array.Empty<int>();
            var expected = 0;

            var actual = Solution.FindMaxArea(heights);

            actual.Should().Be(expected);
        }

        [Test]
        public void FindMaxArea_ShouldPassExampleOne()
        {
            var heights = new[] {1, 8, 6, 2, 5, 4, 8, 3, 7};
            var expected = 49;

            var actual = Solution.FindMaxArea(heights);

            actual.Should().Be(expected);
        }

        [Test]
        public void FindMaxArea_ShouldPassExampleTwo()
        {
            var heights = new[] {1, 3, 1};
            var expected = 2;

            var actual = Solution.FindMaxArea(heights);

            actual.Should().Be(expected);
        }

        [Test]
        public void FindMaxArea_ShouldPass_WhenOnlySameHeights()
        {
            var heights = new[] {2, 2, 2, 2};
            var expected = 6;

            var actual = Solution.FindMaxArea(heights);

            actual.Should().Be(expected);
        }
    }
}