Fix #279 throw ArgumentNullException if bulkdescriptor has no operations defined on it

Author: Mpdreamz

src/Nest.Tests.Integration/Core/Bulk/BulkTests.cs

@@ -18,8 +18,8 @@ public void Bulk()
 		{
 			var result = this._client.Bulk(b => b
 				.Index<ElasticSearchProject>(i => i.Object(new ElasticSearchProject {Id = 2}))
-				.Create<ElasticSearchProject>(i => i.Object(new ElasticSearchProject { Id = 123123 }))
 				.Delete<ElasticSearchProject>(i => i.Object(new ElasticSearchProject { Id = 4 }))
+				.Create<ElasticSearchProject>(i => i.Object(new ElasticSearchProject { Id = 123123 }))
 
 			);
 			result.Should().NotBeNull();

src/Nest/ElasticClient-Bulk.cs

@@ -23,6 +23,7 @@ public IBulkResponse Bulk(Func<BulkDescriptor, BulkDescriptor> bulkSelector)
 		public IBulkResponse Bulk(BulkDescriptor bulkDescriptor)
 		{
 			bulkDescriptor.ThrowIfNull("bulkDescriptor");
+			bulkDescriptor._Operations.ThrowIfEmpty("Bulk descriptor does not define any operations");
 			var sb = new StringBuilder();
 
 			foreach (var operation in bulkDescriptor._Operations)
@@ -120,7 +121,7 @@ private string GenerateBulkDeleteCommand<T>(IEnumerable<BulkParameters<T>> @obje
 
 		private string GenerateBulkCommand<T>(IEnumerable<T> objects, string command) where T : class
 		{
-			objects.ThrowIfNull("objects");
+			objects.ThrowIfEmpty("objects");
 
 			var index = this.IndexNameResolver.GetIndexForType<T>();
 			if (string.IsNullOrEmpty(index))
@@ -130,7 +131,7 @@ private string GenerateBulkCommand<T>(IEnumerable<T> objects, string command) wh
 		}
 		private string GenerateBulkCommand<T>(IEnumerable<BulkParameters<T>> objects, string command) where T : class
 		{
-			objects.ThrowIfNull("objects");
+			objects.ThrowIfEmpty("objects");
 
 			var index = this.IndexNameResolver.GetIndexForType<T>();
 			if (string.IsNullOrEmpty(index))