UppercaseCounter Kata

Source.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Sample
{
    public class UppercaseSearcher
    {
        internal int[] Search(string source)
        {
            var result = new List<int>();
            if (source.Length > 0)
            {
                for (int i = 0; i < source.Length; i++)
                {
                    var current = source[i];
                    if (char.IsUpper(source, i))
                    {
                        result.Add(i);
                    }
                }
                
            }
            return result.ToArray();
        }

        private bool IsUpperCase(char current)
        {
            return current.ToString().ToUpper()
                                    == current.ToString();
        }
    }
}

Test.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xunit;
using Xunit.Extensions;

namespace Sample
{
    public class Test
    {
        [Fact]
        public void ShouldReturnEmptyArrayIfEmptyString()
        { 
            //Arrange
            var source = "";
            var searcher = new UppercaseSearcher();
            
            //Act
            var result = searcher.Search(source);

            //Assert
            Assert.Empty(result);
        }

        [Fact]
        public void ShouldReturnValidUppercaseLocation()
        { 
            //Arrange
            var source = "A";
            var searcher = new UppercaseSearcher();

            //Act
            var result = searcher.Search(source);

            //Assert
            Assert.Equal(1, result.Length);
            Assert.Equal(0, result[0]);
        }

        [Fact]
        public void ShouldReturnValidUppercaseInSecondPlace()
        {
            //Arrange
            var source = "bA";
            var searcher = new UppercaseSearcher();
            var expected = new int[] { 1 };
            //Act
            var result = searcher.Search(source);

            //Assert
            Assert.Equal(expected, result);
        }

        [Theory]
        [InlineData("A", new int[] { 0 })]
        [InlineData("bA", new int[] { 1 })]
        [InlineData("bbAab", new int[] { 2 })]
        [InlineData("babC", new int[] { 3 })]
        //Multiple uppercases
        [InlineData("bCbC", new int[] {1,3})]
        //No uppercase
        [InlineData("qwerty", new int[] { })]
        public void ShouldBeValidInDifferentSituations(string source, int[] expected)
        {
            //Arrange
            var searcher = new UppercaseSearcher();

            //Act
            var result = searcher.Search(source);

            //Assert
            Assert.Equal(expected, result);
        }
    }
}