fix #75 Empty arrays fail to serialize

Author: Michaël Catanzariti

src/Dahomey.Cbor.Tests/CollectionTests.cs

@@ -105,5 +105,56 @@ public void WriteObjectList()
 
             Helper.TestWrite(lst, hexBuffer);
         }
+
+        [Fact]
+        public void ReadEmptyArray()
+        {
+            string hexBuffer = "80";
+            int[] array = Helper.Read<int[]>(hexBuffer);
+
+            Assert.Empty(array);
+        }
+
+        [Fact]
+        public void WriteEmptyArray()
+        {
+            string hexBuffer = "80";
+            int[] array = { };
+            Helper.TestWrite(array, hexBuffer);
+        }
+
+        [Fact]
+        public void ReadEmptyList()
+        {
+            string hexBuffer = "80";
+            List<int> list = Helper.Read<List<int>>(hexBuffer);
+
+            Assert.Empty(list);
+        }
+
+        [Fact]
+        public void WriteEmptyList()
+        {
+            string hexBuffer = "80";
+            List<int> list = new List<int>();
+            Helper.TestWrite(list, hexBuffer);
+        }
+
+        [Fact]
+        public void ReadEmptyDictionary()
+        {
+            string hexBuffer = "A0";
+            Dictionary<int, int> dict = Helper.Read<Dictionary<int, int>>(hexBuffer);
+
+            Assert.Empty(dict);
+        }
+
+        [Fact]
+        public void WriteEmptyDictionary()
+        {
+            string hexBuffer = "A0";
+            Dictionary<int, int> dict = new Dictionary<int, int>();
+            Helper.TestWrite(dict, hexBuffer);
+        }
     }
 }

src/Dahomey.Cbor/Serialization/Converters/ArrayConverter.cs

@@ -101,6 +101,11 @@ public int GetArraySize(ref WriterContext context)
 
         public bool WriteArrayItem(ref CborWriter writer, ref WriterContext context)
         {
+            if (context.array.Length == 0)
+            {
+                return false;
+            }
+
             _itemConverter.Write(ref writer, context.array[context.index++]);
             return context.index < context.array.Length;
         }