Include stored_scripts response in cluster metadata response. (#3757)

Include stored_scripts response in cluster metadata response.

Fixes #3746

Author: codebrain

src/Nest/Cluster/ClusterState/MetadataState.cs

@@ -15,5 +15,9 @@ public class MetadataState
 		[JsonProperty("templates")]
 		[JsonConverter(typeof(VerbatimDictionaryKeysJsonConverter<string, TemplateMapping>))]
 		public IReadOnlyDictionary<string, TemplateMapping> Templates { get; internal set; }
+
+		[JsonProperty("stored_scripts")]
+		[JsonConverter(typeof(VerbatimDictionaryKeysJsonConverter<string, StoredScriptMapping>))]
+		public IReadOnlyDictionary<string, StoredScriptMapping> StoredScripts { get; internal set; }
 	}
 }

src/Nest/Cluster/ClusterState/StoredScriptMapping.cs

@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace Nest
+{
+	public class StoredScriptMapping
+	{
+		[JsonProperty("lang")]
+		public string Language { get; internal set; }
+
+		[JsonProperty("source")]
+		public string Source { get; internal set; }
+
+		[JsonProperty("options")]
+		public IReadOnlyDictionary<string, string> Options { get; internal set; } = EmptyReadOnly<string, string>.Dictionary;
+	}
+}

src/Tests/Tests/Cluster/ClusterState/ClusterStateApiTests.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using Elastic.Xunit.XunitPlumbing;
 using Elasticsearch.Net;
 using FluentAssertions;
 using Nest;
@@ -102,4 +103,44 @@ protected void Assert(RoutingNodesState routingNodes, string master)
 			node.State.Should().NotBeNullOrWhiteSpace();
 		}
 	}
+
+	[SkipVersion("<6.5.0", "Validated against 6.5.0")]
+	public class ClusterStateStoredScriptApiTests
+		: ApiIntegrationTestBase<WritableCluster, IClusterStateResponse, IClusterStateRequest, ClusterStateDescriptor, ClusterStateRequest>
+	{
+		public ClusterStateStoredScriptApiTests(WritableCluster cluster, EndpointUsage usage) : base(cluster, usage) { }
+
+		protected override void IntegrationSetup(IElasticClient client, CallUniqueValues values)
+		{
+			client.PutScript("my-script-id", s => s.Painless("return 0"));
+			client.PutScript("my-other-script-id", s => s.Painless("return 1"));
+		}
+
+		protected override bool ExpectIsValid => true;
+		protected override int ExpectStatusCode => 200;
+		protected override HttpMethod HttpMethod => HttpMethod.GET;
+		protected override string UrlPath => "/_cluster/state/metadata";
+
+		protected override LazyResponses ClientUsage() => Calls(
+			(client, f) => client.ClusterState(s => s.Metric(ClusterStateMetric.Metadata)),
+			(client, f) => client.ClusterStateAsync(s => s.Metric(ClusterStateMetric.Metadata)),
+			(client, r) => client.ClusterState(new ClusterStateRequest(ClusterStateMetric.Metadata)),
+			(client, r) => client.ClusterStateAsync(new ClusterStateRequest(ClusterStateMetric.Metadata))
+		);
+
+		protected override void ExpectResponse(IClusterStateResponse response)
+		{
+			response.Metadata.Should().NotBeNull();
+			response.Metadata.StoredScripts.Should().NotBeNull();
+			response.Metadata.StoredScripts.Count.Should().Be(2);
+
+			response.Metadata.StoredScripts["my-script-id"].Language.Should().Be("painless");
+			response.Metadata.StoredScripts["my-script-id"].Source.Should().Be("return 0");
+			response.Metadata.StoredScripts["my-script-id"].Options.Should().BeEmpty();
+
+			response.Metadata.StoredScripts["my-other-script-id"].Language.Should().Be("painless");
+			response.Metadata.StoredScripts["my-other-script-id"].Source.Should().Be("return 1");
+			response.Metadata.StoredScripts["my-other-script-id"].Options.Should().BeEmpty();
+		}
+	}
 }