fix(test): stop Redis fixture aborting on first connection attempt

src/Redis/test/Eventuous.Tests.Redis/Fixtures/IntegrationFixture.cs

@@ -15,6 +15,7 @@ public sealed class IntegrationFixture : IAsyncInitializer, IAsyncDisposable {
 
     readonly ActivityListener _listener       = DummyActivityListener.Create();
     RedisContainer            _redisContainer = null!;
+    ConnectionMultiplexer     _muxer          = null!;
 
     IEventSerializer Serializer { get; } = new DefaultEventSerializer(TestPrimitives.DefaultOptions);
 
@@ -25,6 +26,14 @@ public async Task InitializeAsync() {
 
         await _redisContainer.StartAsync();
         var connString = _redisContainer.GetConnectionString();
+
+        // FLUSHDB in test teardown is an admin command; StackExchange.Redis 3.x enforces the
+        // admin gate for raw commands issued through Execute as well.
+        // abortConnect=false keeps the multiplexer retrying when the first connection attempt
+        // races the freshly started container. The multiplexer is shared by all tests, as one
+        // connection per process is how StackExchange.Redis is meant to be used.
+        _muxer = await ConnectionMultiplexer.ConnectAsync($"{connString},allowAdmin=true,abortConnect=false");
+
         await Module.LoadModule(GetDb);
 
         GetDatabase = GetDb;
@@ -34,16 +43,11 @@ public async Task InitializeAsync() {
 
         return;
 
-        IDatabase GetDb() {
-            // FLUSHDB in test teardown is an admin command; StackExchange.Redis 3.x enforces the
-            // admin gate for raw commands issued through Execute as well.
-            var muxer = ConnectionMultiplexer.Connect($"{connString},allowAdmin=true");
-
-            return muxer.GetDatabase();
-        }
+        IDatabase GetDb() => _muxer.GetDatabase();
     }
 
     public async ValueTask DisposeAsync() {
+        _muxer.Dispose();
         await _redisContainer.DisposeAsync();
         _listener.Dispose();
     }