public void AddStringElementToArray()
        {
            // Arrange

            var document = new JsonDocument(@"{ 
    'a': { 
        'x': '1'
    },
    'b': '2',
    'c': '3',
    'd': []
}");


            // Act

            document.AddElementToArray(new[] { "d" }, "1");

            var result = document.ToString();


            // Assert

            Assert.Equal(@"{
  ""a"": {
    ""x"": ""1""
  },
  ""b"": ""2"",
  ""c"": ""3"",
  ""d"": [
    ""1""
  ]
}", result, ignoreCase: true, ignoreLineEndingDifferences: true, ignoreWhiteSpaceDifferences: true);
        }