5.4.0 does not allow the same setting to be passed twice on the command line with the latter taking precedence, we now dedup the settings before starting a node when doing integration testing

Author: Mpdreamz

src/Tests/Framework/ManagedElasticsearch/Clusters/ClusterBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using Nest;
 using Tests.Framework.Configuration;
 using Tests.Framework.Integration;

src/Tests/Framework/ManagedElasticsearch/Nodes/NodeConfiguration.cs

@@ -87,6 +87,11 @@ public string[] CreateSettings(string[] additionalSettings)
 			var settingMarker = this.ElasticsearchVersion.Major >= 5 ? "-E " : "-D";
 			return DefaultNodeSettings
 				.Concat(additionalSettings ?? Enumerable.Empty<string>())
+				//allow additional settings to take precedence over already DefaultNodeSettings
+				//without relying on elasticsearch to dedup, 5.4.0 no longer allows passing the same setting twice
+				//on the command with the latter taking precedence
+				.GroupBy(setting => setting.Split(new [] {'='}, 2, StringSplitOptions.RemoveEmptyEntries)[0])
+				.Select(g => g.Last())
 				.Select(s => $"{settingMarker}{s}")
 				.ToArray();
 		}