FunctionScoreQuery: weight should also exist at the query level

Author: gmarz

src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs

@@ -35,6 +35,9 @@ public interface IFunctionScoreQuery : IQuery
 
 		[JsonProperty(PropertyName = "script_score")]
 		IScriptFilter ScriptScore { get; set; }
+
+		[JsonProperty(PropertyName = "weight")]
+		long? Weight { get; set; }
 	}
 
 	public class FunctionScoreQuery : PlainQuery, IFunctionScoreQuery
@@ -52,6 +55,7 @@ protected override void WrapInContainer(IQueryContainer container)
 		public float? MaxBoost { get; set; }
 		public IRandomScoreFunction RandomScore { get; set; }
 		public IScriptFilter ScriptScore { get; set; }
+		public long? Weight { get; set; }
 	}
 
 	public class FunctionScoreQueryDescriptor<T> : IFunctionScoreQuery where T : class
@@ -69,6 +73,8 @@ public class FunctionScoreQueryDescriptor<T> : IFunctionScoreQuery where T : cla
 		IRandomScoreFunction IFunctionScoreQuery.RandomScore { get; set; }
 
 		IScriptFilter IFunctionScoreQuery.ScriptScore { get; set; }
+		
+		long? IFunctionScoreQuery.Weight { get; set; }
 
 		bool IQuery.IsConditionless
 		{
@@ -142,5 +148,11 @@ public FunctionScoreQueryDescriptor<T> ScriptScore(Action<ScriptFilterDescriptor
 
 			return this;
 		}
+
+		public FunctionScoreQueryDescriptor<T> Weight(long weight)
+		{
+			((IFunctionScoreQuery)this).Weight = weight;
+			return this;
+		}
 	}
 }

src/Tests/Nest.Tests.Unit/Search/Query/Singles/FunctionScoreQueryJson.cs

@@ -47,6 +47,30 @@ public void FunctionScoreQuery()
 			Assert.True(json.JsonEquals(expected), json);
 		}
 
+		[Test]
+		public void FunctionScoreQueryWithJustWeight()
+		{
+			var s = new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
+				.Query(q => q
+					.FunctionScore(fs => fs
+						.Query(qq => qq.MatchAll())
+						.Weight(2)
+					)
+				);
+
+			var json = TestElasticClient.Serialize(s);
+			var expected = @"{ 
+                from: 0, size: 10, 
+				query : {
+                    function_score : { 		
+						query : { match_all : {} },
+						weight : 2
+					}
+				}
+			}";
+			Assert.True(json.JsonEquals(expected), json);
+		}
+
 		[Test]
 		public void FunctionScoreQueryConditionless()
 		{