Add Weight option to function score query

Closes #1071

Author: gmarz

src/Nest/DSL/Query/Functions/IFunctionScoreFunction.cs

@@ -8,22 +8,35 @@ namespace Nest
 	[JsonConverter(typeof(ReadAsTypeConverter<FunctionScoreFunction<object>>))]
 	public interface IFunctionScoreFunction
 	{
+		FilterContainer Filter { get; set; }
+		long? Weight { get; set; }
 	}
 
 	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-	public class FunctionScoreFunction<T> : IFunctionScoreFunction 
+	public class FunctionScoreFunction<T> : IFunctionScoreFunction
 		where T : class
 	{
-		[JsonProperty(PropertyName = "filter")]
-		internal FilterContainer FilterDescriptor { get; set; }
+		IFunctionScoreFunction Self { get { return this; } }
+		
+		[JsonProperty("filter")]
+		FilterContainer IFunctionScoreFunction.Filter { get; set; }
+
+		[JsonProperty("weight")]
+		long? IFunctionScoreFunction.Weight { get; set; }
 
 		public FunctionScoreFunction<T> Filter(Func<FilterDescriptor<T>, FilterContainer> filterSelector)
 		{
 			filterSelector.ThrowIfNull("filterSelector");
 			var filter = new FilterDescriptor<T>();
 			var f = filterSelector(filter);
 
-			this.FilterDescriptor = f;
+			this.Self.Filter = f;
+			return this;
+		}
+
+		public FunctionScoreFunction<T> Weight(long weight)
+		{
+			this.Self.Weight = weight;
 			return this;
 		}
 	}

src/Tests/Nest.Tests.Unit/QueryParsers/Queries/FunctionScoreQueryTests.cs

@@ -17,9 +17,9 @@ public void FunctionScore_Deserializes()
 					.BoostMode(FunctionBoostMode.Average)
 					.MaxBoost(0.95f)
 					.Functions(
-						ff => ff.Gauss(x => x.StartedOn, d => d.Scale("42w")),
-						ff => ff.Linear(x => x.FloatValue, d => d.Scale("0.3")).Filter(lff=>Filter2),
-						ff => ff.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
+						ff => ff.Gauss(x => x.StartedOn, d => d.Scale("42w")).Weight(1),
+						ff => ff.Linear(x => x.FloatValue, d => d.Scale("0.3")).Filter(lff=>Filter2).Weight(2),
+						ff => ff.Exp(x => x.DoubleValue, d => d.Scale("0.5")).Weight(3),
 						ff => ff.BoostFactor(2).Filter(bff=>Filter1)
 					)
 					.Query(qq=>Query1)

src/Tests/Nest.Tests.Unit/Search/Sorting/FunctionScoreTests.cs

@@ -55,34 +55,6 @@ public void TestRandomSortWithSeed()
 
 		[Test]
 		public void TestScriptScore()
-		{
-			var s = new SearchDescriptor<ElasticsearchProject>()
-				.Query(q => q.FunctionScore(
-						fs => fs.ScriptScore(ss => ss.Script("_score / pow(param1, param2)").Params(p => p.Add("param1", 1.75).Add("param2", 4)).Lang("mvel")
-						)
-					)
-				);
-			var json = TestElasticClient.Serialize(s);
-			var expected = @"{
-                          query: {
-                            function_score: {
-                              script_score: {
-                                script: ""_score / pow(param1, param2)"",
-                                params: {
-                                  param1: 1.75,
-                                  param2: 4
-                                },
-                                lang: ""mvel""
-                              }
-                            }
-                          }
-                        }";
-
-			Assert.True(json.JsonEquals(expected), json);
-		}
-
-		[Test]
-		public void TestScriptScoreWithFilter()
 		{
 			var s = new SearchDescriptor<ElasticsearchProject>()
 				.Query(q => q
@@ -97,7 +69,7 @@ public void TestScriptScoreWithFilter()
 								.Lang("mvel")
 							).Filter(filter => filter
 								.Term("term1", "termValue")
-							)
+							).Weight(5)
 						)
 					)
 				);
@@ -119,7 +91,8 @@ public void TestScriptScoreWithFilter()
                                         term : {
                                             ""term1"":""termValue""
                                         }
-                                    }
+                                    },
+									weight: 5
                                 }
                               ]
                             }
@@ -130,7 +103,7 @@ public void TestScriptScoreWithFilter()
 		}
 
 		[Test]
-		public void TestBoostFactorWithFilter()
+		public void TestBoostFactor()
 		{
 			var s = new SearchDescriptor<ElasticsearchProject>().Query(
 				q => q.FunctionScore(
@@ -139,6 +112,7 @@ public void TestBoostFactorWithFilter()
 							.Filter(
 								filter => filter.Term("term1", "termValue")
 							)
+							.Weight(5)
 					)
 				)
 			);
@@ -153,7 +127,8 @@ public void TestBoostFactorWithFilter()
                                         term : {
                                             ""term1"":""termValue""
                                         }
-                                    }
+                                    },
+									weight: 5
                                 }
                               ]
                             }
@@ -164,14 +139,14 @@ public void TestBoostFactorWithFilter()
 		}
 
 		[Test]
-		public void TestDecayFunctionWithFilter()
+		public void TestDecayFunction()
 		{
 			var s = new SearchDescriptor<ElasticsearchProject>().Query(
 				q => q.FunctionScore(
 					fs => fs.Functions(
 						f => f.Gauss("floatValue", g => g.Origin("5").Scale("0.1"))
-							  .Filter(gf => gf.Term("term1", "termValue")
-							)
+							  .Filter(gf => gf.Term("term1", "termValue"))
+							  .Weight(5)
 						)
 					)
 				);
@@ -191,7 +166,8 @@ public void TestDecayFunctionWithFilter()
 										""term"": {
 										  ""term1"": ""termValue""
 										}
-									  }
+									  },
+									 ""weight"": 5
 									}
 								  ]
 								}