Fix #1447: Add explanation to validate response

Also found a bug where Valid had an incorrect json property name

Author: gmarz

src/Nest/Domain/Hit/ValidationExplanation.cs

@@ -10,10 +10,14 @@ public class ValidationExplanation
 	{
 		[JsonProperty(PropertyName = "index")]
 		public string Index { get; internal set; }
-		[JsonProperty(PropertyName = "description")]
+
+		[JsonProperty(PropertyName = "valid")]
 		public bool Valid { get; internal set; }
+		
 		[JsonProperty(PropertyName = "error")]
-		public string Error { get; internal set; }
-		
+		public string Error { get; internal set; }
+		
+		[JsonProperty(PropertyName = "explanation")]
+		public string Explanation { get; internal set; }
 	}
 }

src/Tests/Nest.Tests.Integration/Core/ValidateTests.cs

@@ -2,6 +2,7 @@
 using Nest.Tests.MockData.Domain;
 using System.Linq;
 using Elasticsearch.Net;
+using FluentAssertions;
 
 namespace Nest.Tests.Integration.Core
 {
@@ -16,26 +17,42 @@ public void TestValidation()
 					.Term(f=>f.Country, "netherlands")
 				)
 			);
-			Assert.NotNull(response);
-			Assert.True(response.IsValid);
-			Assert.True(response.Valid);
+			response.Should().NotBeNull();
+			response.IsValid.Should().BeTrue();
+			response.Valid.Should().BeTrue();			
 		}
 		[Test]
-		public void TestValidationWithExplain()
+		public void TestValidationWithExplain_Invalid()
 		{
 			var response = this.Client.Validate<ElasticsearchProject>(q => q
 				.Explain()
 				.Q("loc:asdasd")
 			);
-			Assert.NotNull(response);
-			Assert.True(response.IsValid);
-			Assert.False(response.Valid);
-			Assert.NotNull(response.Explanations);
-			Assert.True(response.Explanations.HasAny());
+			response.Should().NotBeNull();
+			response.IsValid.Should().BeTrue();
+			response.Valid.Should().BeFalse();
+			response.Explanations.Should().NotBeNull().And.NotBeEmpty();
 			var explanation = response.Explanations.First();
-			Assert.AreEqual(explanation.Index, Settings.DefaultIndex);
-			Assert.False(explanation.Valid);
-			Assert.False(explanation.Error.IsNullOrEmpty());
+			explanation.Index.Should().BeEquivalentTo(Settings.DefaultIndex);
+			explanation.Valid.Should().BeFalse();
+			explanation.Error.Should().NotBeNullOrEmpty();
+		}
+
+		[Test]
+		public void TestValidationWithExplanation_Valid()
+		{
+			var response = this.Client.Validate<ElasticsearchProject>(v => v
+				.Explain()
+				.Q("name:elasticsearch")
+			);
+			response.Should().NotBeNull();
+			response.IsValid.Should().BeTrue();
+			response.Explanations.Should().NotBeNull().And.NotBeEmpty();
+			var explanation = response.Explanations.First();
+			explanation.Index.Should().BeEquivalentTo(Settings.DefaultIndex);
+			explanation.Valid.Should().BeTrue();
+			explanation.Error.Should().BeNullOrEmpty();
+			explanation.Explanation.Should().NotBeNullOrEmpty();
 		}
 	}
 }