skip rather than fail if dedicated database isn't available

StackExchange.Redis.Tests/Booksleeve/Issues/Massive Delete.cs

@@ -15,6 +15,7 @@ private void Prep(int db, string key)
             var prefix = Me();
             using (var muxer = GetUnsecuredConnection(allowAdmin: true))
             {
+                Skip.IfMissingDatabase(muxer, db);
                 GetServer(muxer).FlushDatabase(db);
                 Task last = null;
                 var conn = muxer.GetDatabase(db);

StackExchange.Redis.Tests/Databases.cs

@@ -15,12 +15,16 @@ public async Task CountKeys()
             var db2Id = TestConfig.GetDedicatedDB();
             using (var muxer = Create(allowAdmin: true))
             {
+                Skip.IfMissingDatabase(muxer, db1Id);
+                Skip.IfMissingDatabase(muxer, db2Id);
                 var server = GetAnyMaster(muxer);
                 server.FlushDatabase(db1Id, CommandFlags.FireAndForget);
                 server.FlushDatabase(db2Id, CommandFlags.FireAndForget);
             }
             using (var muxer = Create())
             {
+                Skip.IfMissingDatabase(muxer, db1Id);
+                Skip.IfMissingDatabase(muxer, db2Id);
                 RedisKey key = Me();
                 var db61 = muxer.GetDatabase(db1Id);
                 var db62 = muxer.GetDatabase(db2Id);
@@ -43,9 +47,9 @@ public void MultiDatabases()
             using (var muxer = Create())
             {
                 RedisKey key = Me();
-                var db0 = muxer.GetDatabase(TestConfig.GetDedicatedDB());
-                var db1 = muxer.GetDatabase(TestConfig.GetDedicatedDB());
-                var db2 = muxer.GetDatabase(TestConfig.GetDedicatedDB());
+                var db0 = muxer.GetDatabase(TestConfig.GetDedicatedDB(muxer));
+                var db1 = muxer.GetDatabase(TestConfig.GetDedicatedDB(muxer));
+                var db2 = muxer.GetDatabase(TestConfig.GetDedicatedDB(muxer));
                 db0.Ping();
 
                 db0.KeyDelete(key, CommandFlags.FireAndForget);

StackExchange.Redis.Tests/Helpers/Skip.cs

@@ -34,6 +34,12 @@ public static void IfMissingFeature(ConnectionMultiplexer conn, string feature,
                 };
             }
         }
+
+        internal static void IfMissingDatabase(ConnectionMultiplexer conn, int dbId)
+        {
+            var dbCount = conn.GetServer(conn.GetEndPoints()[0]).DatabaseCount;
+            if (dbId >= dbCount) throw new SkipTestException($"Database {dbId} is not supported on this server.");
+        }
     }
 
 #pragma warning disable RCS1194 // Implement exception constructors.

StackExchange.Redis.Tests/Helpers/TestConfig.cs

@@ -12,7 +12,12 @@ public static class TestConfig
         public static Config Current { get; }
 
         private static int _db = 17;
-        public static int GetDedicatedDB() => Interlocked.Increment(ref _db);
+        public static int GetDedicatedDB(ConnectionMultiplexer conn = null)
+        {
+            int db = Interlocked.Increment(ref _db);
+            if (conn != null) Skip.IfMissingDatabase(conn, db);
+            return db;
+        }
 
         static TestConfig()
         {

StackExchange.Redis.Tests/Keys.cs

@@ -34,7 +34,8 @@ public void FlushFetchRandomKey()
         {
             using (var conn = Create(allowAdmin: true))
             {
-                var dbId = TestConfig.GetDedicatedDB();
+                var dbId = TestConfig.GetDedicatedDB(conn);
+                Skip.IfMissingDatabase(conn, dbId);
                 var db = conn.GetDatabase(dbId);
                 var prefix = Me();
                 conn.GetServer(TestConfig.Current.MasterServerAndPort).FlushDatabase(dbId);

StackExchange.Redis.Tests/Scans.cs

@@ -18,7 +18,7 @@ public void KeysScan(bool supported)
             string[] disabledCommands = supported ? null : new[] { "scan" };
             using (var conn = Create(disabledCommands: disabledCommands, allowAdmin: true))
             {
-                var dbId = TestConfig.GetDedicatedDB();
+                var dbId = TestConfig.GetDedicatedDB(conn);
                 var db = conn.GetDatabase(dbId);
                 var prefix = Me() + ":";
                 var server = GetServer(conn);
@@ -44,7 +44,7 @@ public void ScansIScanning()
             using (var conn = Create(allowAdmin: true))
             {
                 var prefix = Me() + Guid.NewGuid();
-                var dbId = TestConfig.GetDedicatedDB();
+                var dbId = TestConfig.GetDedicatedDB(conn);
                 var db = conn.GetDatabase(dbId);
                 var server = GetServer(conn);
                 server.FlushDatabase(dbId);
@@ -93,7 +93,7 @@ public void ScanResume()
             {
                 // only goes up to 3.*, so...
                 Skip.IfMissingFeature(conn, nameof(RedisFeatures.Scan), x => x.Scan);
-                var dbId = TestConfig.GetDedicatedDB();
+                var dbId = TestConfig.GetDedicatedDB(conn);
                 var db = conn.GetDatabase(dbId);
                 var prefix = Me();
                 var server = GetServer(conn);

StackExchange.Redis/StackExchange/Redis/Interfaces/IServer.cs

@@ -52,6 +52,11 @@ public partial interface IServer : IRedis
         /// </summary>
         Version Version { get; }
 
+        /// <summary>
+        /// The number of databases supported on this server
+        /// </summary>
+        int DatabaseCount { get; }
+
         /// <summary>
         /// The CLIENT KILL command closes a given client connection identified by ip:port.
         /// The ip:port should match a line returned by the CLIENT LIST command.

StackExchange.Redis/StackExchange/Redis/RedisServer.cs

@@ -18,6 +18,8 @@ internal RedisServer(ConnectionMultiplexer multiplexer, ServerEndPoint server, o
             this.server = server ?? throw new ArgumentNullException(nameof(server));
         }
 
+        int IServer.DatabaseCount => server.Databases;
+
         public ClusterConfiguration ClusterConfiguration => server.ClusterConfiguration;
 
         public EndPoint EndPoint => server.EndPoint;

TestConsole/Program.cs

@@ -13,20 +13,15 @@ private static int Main()
             var watch = Stopwatch.StartNew();
             try
             {
-#if DEBUG
-                // Pipelines.Sockets.Unofficial.DebugCounters.SetLog(Console.Out);
-#endif
 
                 var config = new ConfigurationOptions
                 {
                     ConnectRetry = 0,
-                    EndPoints = { "127.0.0.1:6381" },
-                    Password = "abc",
+                    EndPoints = { "127.0.0.1:6379" },
                 };
-                using (var conn = ConnectionMultiplexer.Connect(config, log: null))
+                using (var conn = ConnectionMultiplexer.Connect(config, log: Console.Out))
                 {
-                    //Execute(conn);
-                    
+                    Execute(conn);                   
 
                 }
                 return 0;
@@ -46,14 +41,14 @@ private static int Main()
 
         private static void Execute(ConnectionMultiplexer conn)
         {
+            Console.WriteLine("Executing...");
             var key = "abc";
-            Console.ReadKey();
             var db = conn.GetDatabase(0);
             var t = db.CreateTransaction();
             t.HashSetAsync(key, "foo", "bar");
             t.KeyExpireAsync(key, TimeSpan.FromSeconds(3600));
             t.Execute();
-            Console.ReadKey();
+            Console.WriteLine("Done");
         }
     }
 }