fix unit tests

core/Processors/DefaultStreamPartitioner.cs

@@ -0,0 +1,28 @@
+using Confluent.Kafka;
+
+namespace Streamiz.Kafka.Net.Processors
+{
+    /// <summary>
+    /// Forward the source partition as the sink partition of the record if there is enough sink partitions, Partition.Any otherwise
+    /// </summary>
+    /// <typeparam name="K">Key record type</typeparam>
+    /// <typeparam name="V">Value record type</typeparam>
+    public class DefaultStreamPartitioner<K, V> : IStreamPartitioner<K, V>
+    {
+        /// <summary>
+        /// Function used to determine how records are distributed among partitions of the topic
+        /// </summary>
+        /// <param name="topic">Sink topic name</param>
+        /// <param name="key">record's key</param>
+        /// <param name="value">record's value</param>
+        /// <param name="sourcePartition">record's source partition</param>
+        /// <param name="numPartitions">number partitions of the sink topic</param>
+        /// <returns>Return the source partition as the sink partition of the record if there is enough sink partitions, Partition.Any otherwise</returns>
+        public Partition Partition(string topic, K key, V value, Partition sourcePartition, int numPartitions)
+        {
+            if (sourcePartition.Value <= numPartitions - 1)
+                return sourcePartition;
+            return Confluent.Kafka.Partition.Any;
+        }
+    }
+}

core/Processors/IStreamPartitioner.cs

@@ -4,6 +4,15 @@ namespace Streamiz.Kafka.Net.Processors
 {
     public interface IStreamPartitioner<K, V>
     {
+        /// <summary>
+        /// Function used to determine how records are distributed among partitions of the topic
+        /// </summary>
+        /// <param name="topic">Sink topic name</param>
+        /// <param name="key">record's key</param>
+        /// <param name="value">record's value</param>
+        /// <param name="sourcePartition">record's source partition</param>
+        /// <param name="numPartitions">number partitions of the sink topic</param>
+        /// <returns>Return the destination partition for the current record</returns>
         Partition Partition(string topic, K key, V value, Partition sourcePartition, int numPartitions);
     }
 }