System.Text.Json.Serialization.JsonStringEnumConverter allows case insensitive enum values by default in .net 5.0

TestCaseInsensitiveJsonStringEnum.cs

using System;
using System.Diagnostics;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace TestCaseInsensitiveJsonStringEnum
{
    [JsonConverter(typeof(JsonStringEnumConverter))]
    public enum Season
    {
        Spring,
        Summer,
        Autumn,
        Winter
    }

    public class YearSeason
    {
        public int Year { get; set; }
        public Season Season { get; set; }
    }

    internal static class Program
    {
        private static readonly JsonSerializerOptions JsonSerializerOptions = new()
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
        };

        static void Main(string[] args)
        {
            TestProperCaseEnumValue();
            TestInproperCaseEnumValue();
            TestInvalidEnumValue();
        }

         private static void TestProperCaseEnumValue()
        {
            const string json = @"
            {
                ""year"": 2022,
                ""season"": ""Summer""
            }
            ";

            var yearsSeasons = JsonSerializer.Deserialize<YearSeason>(json, JsonSerializerOptions);
            Debug.Assert(yearsSeasons is not null);
            Debug.Assert(yearsSeasons.Year == 2022);
            Debug.Assert(yearsSeasons.Season == Season.Summer);
        }

        private static void TestInproperCaseEnumValue()
        {
            const string json = @"
            {
                ""year"": 2022,
                ""season"": ""summER""
            }
            ";

            var yearsSeasons = JsonSerializer.Deserialize<YearSeason>(json, JsonSerializerOptions);
            Debug.Assert(yearsSeasons is not null);
            Debug.Assert(yearsSeasons.Year == 2022);
            Debug.Assert(yearsSeasons.Season == Season.Summer);
        }

        private static void TestInvalidEnumValue()
        {
            const string json = @"
            {
                ""year"": 2022,
                ""season"": ""INVALID_VALUE""
            }
            ";

            try
            {
                JsonSerializer.Deserialize<YearSeason>(json, JsonSerializerOptions);
            }
            catch (JsonException)
            {
                return; // all fine, what's expected
            }

            throw new Exception($"FAIL: Invalid {nameof(Season)} value was silently swallowed.");
        }
    }
}