Unit test using AddCondition from ITransaction does not works

[lpintorj]

Good evening.
How do I mock the method AddCondition from ITransaction?

My class:

public class SampleRedisRepository
{
        private const string cFIELD_STATUS = "STATUS";
        private const string cFIELD_STATUS_TIME = "STATUS_TIME";
        private const string cFIELD_STATUS_DESCRIPTION = "STATUS_DESCRIPTION";
        private const string cPATH = nameof(SampleRedisRepository);
        private const string cFIELD_REQUEST_TYPE = "REQUEST_TYPE";
        private const string cFIELD_CREATION_TIME = "CREATION_TIME";
        private const string cFIELD_STATUS_HISTORY = "STATUS_HISTORY";
        private readonly int _redisDbNumber;
        private readonly IDatabase _database;
        private readonly ILogger<SampleRedisRepository> _logger;

        public SampleRedisRepository(IDatabase database, ILogger<SampleRedisRepository> logger, int redisDbNumber)
        {
            _database = database ?? throw new ArgumentNullException(nameof(database));
            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
            _redisDbNumber = redisDbNumber;
        }

        public void Create<TRequest>(Guid requestId) where TRequest : class
        {
            var requestType = typeof(TRequest).FullName;
            var key = CreateKey(requestId);
            var redisTime = GetRedisTime();

            var tran = _database.CreateTransaction();

            var crKeyNotExists = tran.AddCondition(Condition.KeyNotExists(key));

            tran.HashSetAsync(key, new HashEntry[] {
                new HashEntry(cFIELD_REQUEST_TYPE, requestType),
                new HashEntry(cFIELD_CREATION_TIME, redisTime),
                new HashEntry(cFIELD_STATUS, $"{ERequestStatus.InProgress}"),
                new HashEntry(cFIELD_STATUS_TIME, redisTime),
                new HashEntry(cFIELD_STATUS_DESCRIPTION, "created"),
             });

            if (tran.Execute())
            {
                _logger.LogDebug($"Request Id:{requestId} created.");
                return;
            }

            if (!crKeyNotExists.WasSatisfied)
                throw new InvalidOperationException($"Request Id:{requestId} already exists.");

            throw new InvalidOperationException($"Error on create request Id:{requestId}.");
        }

        private long GetRedisTime() => (long)_database.ScriptEvaluate("return redis.call('TIME')[1]");

        public static RedisKey CreateKey(Guid requestId) => $"{cPATH}:{requestId}";
}

My unit test:

[Fact]
public void Create_Test()
{
            int redisNumber = 2;
            Guid requestId = Guid.NewGuid();
            var key = SampleRedisRepository.CreateKey(requestId);
            RedisResult redisTime = RedisResult.Create(123456);

            var mqTransaction = new Mock<ITransaction>();
            mqTransaction
                .Setup(t => t.AddCondition(Condition.KeyNotExists(key)))
                .Returns(????); // => PROBLEM!! How do I create an instance of ConditionResult ??

            var mqDatabase = new Mock<IDatabase>();
            mqDatabase
                .Setup(d => d.CreateTransaction(It.IsAny<object?>()))
                .Returns(mqTransaction.Object);

            mqDatabase
                .Setup(d => d.ScriptEvaluate("return redis.call('TIME')[1]", It.IsAny<RedisKey[]?>(), It.IsAny<RedisValue[]?>(), It.IsAny<CommandFlags>()))
                .Returns(redisTime);

            var initialData = new Dictionary<string, string>()
            {
                { "Redis:DbNumber", redisNumber.ToString() }
            };

            var configuration = new ConfigurationBuilder()
                .AddInMemoryCollection(initialData)
                .Build();

            var repository = new SampleRedisRepository(mqDatabase.Object, Mock.Of<ILogger<SampleRedisRepository>>(), redisNumber);

            repository.Create<SimpleClassToTest>(requestId);

            mqDatabase.Verify(c => c.CreateTransaction(It.IsAny<object?>()), Times.Once());

            mqTransaction.Verify(c => c.HashSetAsync(
                key,
                It.Is<HashEntry[]>(he => he.Any(
                    h => h.Name.Equals("STATUS")
                    && h.Value.Equals($"{ERequestStatus.InProgress}")
                    && h.Name.Equals("REQUEST_TYPE")
                    && h.Value.Equals(typeof(SimpleClassToTest).FullName)
                    && h.Name.Equals("STATUS_DESCRIPTION")
                    && h.Value.Equals("created")
                    && h.Name.Equals("STATUS_TIME")
                    && h.Value.Equals(redisTime)
                )),
                It.IsAny<CommandFlags>()), Times.Once());
}

I cannot create an instance of ConditionResult because the constructor is internal. See line 827 of Condition.cs

Many thanks.

[lpintorj]

I know I could create adapters/wrappers to solve it. By the way I did. But I want to know if I could implement this unit test without adapters/wrappers.

[NickCraver]

Hmm, there's not a way to currently do this - it's pretty internal because even if we exposed it all the downstream properties are further blocks to make use of the result. Which members of ConditionResult are you wanting to access in the end?

[kmcclellan]

The need is to 1) create an instance that is not tied to a real multiplexer, and 2) stub the value of WasSatisfied. As an abstraction, ITransaction members should also return abstractions.

public interface IConditionResult
{
    bool WasSatisfied { get; }
}

[kmcclellan]

Sure enough, I find myself working on a bug with Redis transaction code that didn't have test coverage because of this issue.

The issue is serious enough that I am going back and adding tests despite the pain points. I have had success using reflection to stub the condition result:

internal sealed class FakeRedis
{
    private static ConstructorInfo? _conditionResultConstructor;
    private static FieldInfo? _conditionResultWasSatisfiedField;

    public static ConditionResult GetConditionResult(bool satisfied)
    {
        _conditionResultConstructor ??= typeof(ConditionResult)
            .GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, new[] { typeof(Condition) }) ??
                throw new InvalidOperationException($"Constructor not found for '{typeof(ConditionResult)}'.");

        _conditionResultWasSatisfiedField ??= typeof(ConditionResult)
            .GetField("wasSatisfied", BindingFlags.Instance | BindingFlags.NonPublic) ??
                throw new InvalidOperationException($"Field 'wasSatisfied' not found for '{typeof(ConditionResult)}'.");

        var result = _conditionResultConstructor.Invoke(parameters: new[] { default(object) });

        if (satisfied)
        {
            _conditionResultWasSatisfiedField.SetValue(result, value: true);
        }

        return (ConditionResult)result;
    }
}

Of course, I don't like having to invoke internal/private members. I still think the contract for ITransaction should be changed but providing a public API to create stubbed results like this would also help.