Tests: enable Sentinel

StackExchange.Redis.Tests/Helpers/TestConfig.cs

@@ -58,7 +58,7 @@ public class Config
             public string RemoteServer { get; set; } = "127.0.0.1";
             public int RemotePort { get; set; } = 6379;
 
-            public string SentinelServer { get; set; }
+            public string SentinelServer { get; set; } = "127.0.0.1";
             public int SentinelPort { get; set; } = 26379;
             public string SentinelSeviceName { get; set; } = "mymaster";
 

StackExchange.Redis.Tests/Sentinel.cs

@@ -101,7 +101,7 @@ public void SentinelSlavesTest()
             }
         }
 
-        [Fact(Skip = "Isolated Test")]
+        [Fact]
         public void SentinelFailoverTest()
         {
             Server.SentinelFailover(ServiceName);