add integration test (and fix CI)

Author: mgravell

tests/StackExchange.Redis.Tests/RedisValueSequenceServerTests.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Buffers;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace StackExchange.Redis.Tests;
+
+/// <summary>
+/// Round-trips a multi-segment <see cref="ReadOnlySequence{T}"/>-backed <see cref="RedisValue"/>
+/// (<see cref="RedisValue.StorageType.Sequence"/>) through the shared in-process server via
+/// StringSet/StringGet, exercising the segmented write path in <c>MessageWriter</c>.
+/// </summary>
+public class RedisValueSequenceServerTests(ITestOutputHelper output, InProcServerFixture fixture) : TestBase(output, fixture)
+{
+    // one segment per byte => a genuinely multi-segment sequence (StorageType.Sequence)
+    private static RedisValue MultiSegment(byte[] payload)
+    {
+        var chunks = new ReadOnlyMemory<byte>[payload.Length];
+        for (int i = 0; i < payload.Length; i++)
+        {
+            chunks[i] = new ReadOnlyMemory<byte>(payload, i, 1);
+        }
+        return FragmentedSegment<byte>.Create(chunks);
+    }
+
+    [Fact]
+    public async Task StringSet_MultiSegmentSequence_RoundTrips()
+    {
+        await using var conn = Create();
+        var db = conn.GetDatabase();
+        var key = Me();
+        db.KeyDelete(key, CommandFlags.FireAndForget);
+
+        var payload = Encoding.UTF8.GetBytes("the quick brown fox jumps over the lazy dog");
+        RedisValue value = MultiSegment(payload);
+        Assert.Equal(RedisValue.StorageType.Sequence, value.Type);
+
+        Assert.True(db.StringSet(key, value));
+
+        var roundTripped = db.StringGet(key);
+        Assert.Equal(payload, (byte[]?)roundTripped);
+    }
+
+    [Fact]
+    public async Task StringSetAsync_MultiSegmentSequence_RoundTrips()
+    {
+        await using var conn = Create();
+        var db = conn.GetDatabase();
+        var key = Me();
+        await db.KeyDeleteAsync(key);
+
+        var payload = Encoding.UTF8.GetBytes("a multi-segment sequence payload long enough to span several segments");
+        RedisValue value = MultiSegment(payload);
+        Assert.Equal(RedisValue.StorageType.Sequence, value.Type);
+
+        Assert.True(await db.StringSetAsync(key, value));
+
+        var roundTripped = await db.StringGetAsync(key);
+        Assert.Equal(payload, (byte[]?)roundTripped);
+    }
+}

tests/StackExchange.Redis.Tests/RedisValueSequenceTests.cs

@@ -182,8 +182,8 @@ public void MultiSegmentSequence_CompareTo_EqualContentDifferentBoundaries()
     {
         // identical content, but segmented differently on each side - the tandem walk must still see equality
         var bytes = Encoding.UTF8.GetBytes("the quick brown fox");
-        RedisValue a = FragmentedSegment<byte>.Create(bytes[..4], bytes[4..11], bytes[11..]);
-        RedisValue b = FragmentedSegment<byte>.Create(bytes[..2], bytes[2..9], bytes[9..15], bytes[15..]);
+        RedisValue a = FragmentedSegment<byte>.Create(Mem(bytes, 0, 4), Mem(bytes, 4, 7), Mem(bytes, 11, bytes.Length - 11));
+        RedisValue b = FragmentedSegment<byte>.Create(Mem(bytes, 0, 2), Mem(bytes, 2, 7), Mem(bytes, 9, 6), Mem(bytes, 15, bytes.Length - 15));
         Assert.Equal(RedisValue.StorageType.Sequence, a.Type);
         Assert.Equal(RedisValue.StorageType.Sequence, b.Type);
 
@@ -198,8 +198,8 @@ public void MultiSegmentSequence_CompareTo_DifferenceAcrossBoundaries()
         // the differing byte (index 5: 'f' vs 'X') sits in a different segment on each side
         var x = Encoding.UTF8.GetBytes("abcdefgh");
         var y = Encoding.UTF8.GetBytes("abcdeXgh");
-        RedisValue sx = FragmentedSegment<byte>.Create(x[..3], x[3..]); // [abc][defgh]
-        RedisValue sy = FragmentedSegment<byte>.Create(y[..6], y[6..]); // [abcdeX][gh]
+        RedisValue sx = FragmentedSegment<byte>.Create(Mem(x, 0, 3), Mem(x, 3, x.Length - 3)); // [abc][defgh]
+        RedisValue sy = FragmentedSegment<byte>.Create(Mem(y, 0, 6), Mem(y, 6, y.Length - 6)); // [abcdeX][gh]
 
         int expected = Math.Sign(((ReadOnlySpan<byte>)x).SequenceCompareTo(y)); // 'f' > 'X' => positive
         Assert.Equal(expected, Math.Sign(sx.CompareTo(sy)));
@@ -225,4 +225,7 @@ private static RedisValue SplitEveryByte(byte[] bytes)
         }
         return FragmentedSegment<byte>.Create(chunks);
     }
+
+    // a slice of the source as ReadOnlyMemory (no array allocation, and avoids range syntax for net481)
+    private static ReadOnlyMemory<byte> Mem(byte[] source, int start, int length) => new(source, start, length);
 }