UA-.NETStandard/tests/Opc.Ua.Redundancy.Client.Tests/Raft/HybridSharedKeyValueStoreTests.cs

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// IDE0230: byte-array literals below are opaque binary test vectors, not text; a
// UTF-8 "..."u8 literal would misrepresent their intent, so keep the explicit byte arrays.
#pragma warning disable IDE0230 // Use UTF-8 string literal


// CA2000: system-under-test disposables are created per test and released at teardown;
//   there is no cross-test resource leak. Suppressed file-level for the suite.
#pragma warning disable CA2000 // Dispose objects before losing scope

// CA2007: tests run without a SynchronizationContext; ConfigureAwait(false)
// adds noise without a behavioural benefit. Disabled file-level for the suite.
#pragma warning disable CA2007

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using NUnit.Framework;
using Opc.Ua.Redundancy;

namespace Opc.Ua.Client.Redundancy.Tests
{
    /// <summary>
    /// Coverage for <see cref="HybridSharedKeyValueStore"/>: prefix routing between a bulk (CRDT) backend and a strong
    /// (Raft) backend. Two <see cref="InMemorySharedKeyValueStore"/> instances stand in for the backends so routing is
    /// directly observable.
    /// </summary>
    [TestFixture]
    [Category("ClientRedundancy")]
    public sealed class HybridSharedKeyValueStoreTests
    {
        [Test]
        public async Task BulkKeyRoutesToBulkStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);

            (bool inBulk, _) = await bulk.TryGetAsync("node/1").ConfigureAwait(false);
            (bool inStrong, _) = await strong.TryGetAsync("node/1").ConfigureAwait(false);
            Assert.That(inBulk, Is.True, "bulk keys live in the CRDT backend");
            Assert.That(inStrong, Is.False);
        }

        [Test]
        public async Task StrongKeyRoutesToStrongStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.SetAsync("nonce/abc", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);

            (bool inStrong, _) = await strong.TryGetAsync("nonce/abc").ConfigureAwait(false);
            (bool inBulk, _) = await bulk.TryGetAsync("nonce/abc").ConfigureAwait(false);
            Assert.That(inStrong, Is.True, "strong keys live in the Raft backend");
            Assert.That(inBulk, Is.False);
        }

        [Test]
        public async Task CompareAndSwapOnStrongKeyUsesStrongStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);
            var value = ByteString.From(new byte[] { 7 });

            bool created = await hybrid.CompareAndSwapAsync("lease/leader", default, value).ConfigureAwait(false);
            (bool inStrong, _) = await strong.TryGetAsync("lease/leader").ConfigureAwait(false);

            Assert.That(created, Is.True);
            Assert.That(inStrong, Is.True);
        }

        [Test]
        public async Task DeleteRoutesToSelectedStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);
            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/a", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);

            bool deletedBulk = await hybrid.DeleteAsync("node/1").ConfigureAwait(false);
            bool deletedStrong = await hybrid.DeleteAsync("nonce/a").ConfigureAwait(false);

            Assert.That(deletedBulk, Is.True);
            Assert.That(deletedStrong, Is.True);
            (bool foundBulk, _) = await bulk.TryGetAsync("node/1").ConfigureAwait(false);
            (bool foundStrong, _) = await strong.TryGetAsync("nonce/a").ConfigureAwait(false);
            Assert.That(foundBulk, Is.False);
            Assert.That(foundStrong, Is.False);
        }

        [Test]
        public async Task WatchOnStrongPrefixObservesStrongStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));

            await using IAsyncEnumerator<KeyValueChange> enumerator =
                hybrid.WatchAsync("election/", cts.Token).GetAsyncEnumerator(cts.Token);

            ValueTask<bool> first = enumerator.MoveNextAsync();
            await hybrid.SetAsync("election/leader", ByteString.From(new byte[] { 1 }), cts.Token)
                .ConfigureAwait(false);

            Assert.That(await first.ConfigureAwait(false), Is.True);
            Assert.That(enumerator.Current.Key, Is.EqualTo("election/leader"));
        }

        [Test]
        public async Task WatchOnBulkPrefixObservesBulkStoreAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));

            await using IAsyncEnumerator<KeyValueChange> enumerator =
                hybrid.WatchAsync("node/", cts.Token).GetAsyncEnumerator(cts.Token);

            ValueTask<bool> first = enumerator.MoveNextAsync();
            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 }), cts.Token).ConfigureAwait(false);

            Assert.That(await first.ConfigureAwait(false), Is.True);
            Assert.That(enumerator.Current.Key, Is.EqualTo("node/1"));
        }

        [Test]
        public async Task EmptyPrefixScanMergesBothStoresAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/a", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);

            var keys = new List<string>();
            await foreach (KeyValuePair<string, ByteString> entry in hybrid.ScanAsync(string.Empty)
                .ConfigureAwait(false))
            {
                keys.Add(entry.Key);
            }

            Assert.That(keys, Is.EquivalentTo(["node/1", "nonce/a"]));
        }

        [Test]
        public async Task StrongPrefixScanReturnsStrongKeysOnlyAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/a", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/b", ByteString.From(new byte[] { 3 })).ConfigureAwait(false);

            var keys = new List<string>();
            await foreach (KeyValuePair<string, ByteString> entry in hybrid.ScanAsync("nonce/").ConfigureAwait(false))
            {
                keys.Add(entry.Key);
            }

            Assert.That(keys, Is.EquivalentTo(["nonce/a", "nonce/b"]));
        }

        [Test]
        public async Task BulkPrefixScanReturnsBulkKeysOnlyAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("node/2", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/a", ByteString.From(new byte[] { 3 })).ConfigureAwait(false);

            var keys = new List<string>();
            await foreach (KeyValuePair<string, ByteString> entry in hybrid.ScanAsync("node/").ConfigureAwait(false))
            {
                keys.Add(entry.Key);
            }

            Assert.That(keys, Is.EquivalentTo(["node/1", "node/2"]),
                "a bulk-only prefix must not enumerate the strong store");
        }

        [Test]
        public async Task IsStrongKeyClassifiesByPrefixAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            Assert.That(hybrid.IsStrongKey("nonce/x"), Is.True);
            Assert.That(hybrid.IsStrongKey("lease/x"), Is.True);
            Assert.That(hybrid.IsStrongKey("election/x"), Is.True);
            Assert.That(hybrid.IsStrongKey("node/x"), Is.False);
            Assert.That(hybrid.IsStrongKey(null!), Is.False, "a null key is treated as a bulk key");
        }

        [Test]
        public async Task SetWithNullKeyThrowsAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            Assert.That(
                async () => await hybrid.SetAsync(null!, ByteString.Empty).ConfigureAwait(false),
                Throws.TypeOf<ArgumentNullException>());
        }

        [Test]
        public async Task CustomStrongPrefixReplacesDefaultsAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            var prefixes = new ArrayOf<string>(s_stringValues1.AsMemory());
            await using var hybrid = new HybridSharedKeyValueStore(bulk, strong, prefixes);

            await hybrid.SetAsync("cas/x", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/y", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);

            (bool casInStrong, _) = await strong.TryGetAsync("cas/x").ConfigureAwait(false);
            (bool nonceInBulk, _) = await bulk.TryGetAsync("nonce/y").ConfigureAwait(false);
            Assert.That(casInStrong, Is.True, "the custom prefix routes to the strong store");
            Assert.That(nonceInBulk, Is.True, "custom prefixes replace the defaults, so nonce/ is now a bulk key");
        }

        [Test]
        public async Task OwnsStoresDisposesAsyncAndSyncBackendsAsync()
        {
            // bulk is an IDisposable backend, strong is an IAsyncDisposable
            // backend, so disposing the hybrid exercises both dispose paths.
            var bulk = new InMemorySharedKeyValueStore();
            var strong = new RaftSharedKeyValueStore();
            var hybrid = new HybridSharedKeyValueStore(bulk, strong, default, ownsStores: true);

            await hybrid.SetAsync("node/1", ByteString.From(new byte[] { 1 })).ConfigureAwait(false);
            await hybrid.SetAsync("nonce/a", ByteString.From(new byte[] { 2 })).ConfigureAwait(false);
            await hybrid.DisposeAsync().ConfigureAwait(false);

            // InMemorySharedKeyValueStore.Dispose clears its data, so a miss here
            // proves the synchronous IDisposable backend was disposed.
            (bool foundInBulk, _) = await bulk.TryGetAsync("node/1").ConfigureAwait(false);
            Assert.That(foundInBulk, Is.False, "the synchronous IDisposable backend was disposed");

            // The Raft backend disposes its owned consensus, so a subsequent
            // mutation faults - proving the IAsyncDisposable backend was disposed.
            Assert.That(
                async () => await strong.SetAsync("nonce/b", ByteString.From(new byte[] { 3 })).ConfigureAwait(false),
                Throws.InstanceOf<ObjectDisposedException>(), "the asynchronous IAsyncDisposable backend was disposed");
        }

        [Test]
        public async Task DisposeIsIdempotentAsync()
        {
            using var bulk = new InMemorySharedKeyValueStore();
            using var strong = new InMemorySharedKeyValueStore();
            var hybrid = new HybridSharedKeyValueStore(bulk, strong);

            await hybrid.DisposeAsync().ConfigureAwait(false);
            Assert.That(async () => await hybrid.DisposeAsync().ConfigureAwait(false), Throws.Nothing);
        }

        [Test]
        public void DefaultStrongKeyPrefixesExposesTheDefaults()
        {
            ArrayOf<string> defaults = HybridSharedKeyValueStore.DefaultStrongKeyPrefixes;

            Assert.That(defaults.Count, Is.EqualTo(3));
            Assert.That(defaults[0], Is.EqualTo("nonce/"));
            Assert.That(defaults[1], Is.EqualTo("lease/"));
            Assert.That(defaults[2], Is.EqualTo("election/"));
        }

        private static readonly string[] s_stringValues1 = ["cas/"];
    }
}