Serialisers throw clearer exceptions when asked to serialise to null Stream/packer.

Author: drewnoakes

Dasher.Tests/SerialiserTests.cs

@@ -22,6 +22,7 @@
 //
 #endregion
 
+using System;
 using System.IO;
 using Xunit;
 
@@ -99,6 +100,30 @@ public void HandlesClassWrappingCustomStruct()
             Assert.Equal(123, after.Value.Score);
         }
 
+        [Fact]
+        public void ThrowsIfNullStream()
+        {
+            var ex = Assert.Throws<ArgumentNullException>(() => new Serialiser<UserScore>().Serialise((Stream)null, new UserScore("Doug", 100)));
+
+            Assert.Equal("stream", ex.ParamName);
+
+            ex = Assert.Throws<ArgumentNullException>(() => new Serialiser(typeof(UserScore)).Serialise((Stream)null, new UserScore("Doug", 100)));
+
+            Assert.Equal("stream", ex.ParamName);
+        }
+
+        [Fact]
+        public void ThrowsIfNullPacker()
+        {
+            var ex = Assert.Throws<ArgumentNullException>(() => new Serialiser<UserScore>().Serialise((UnsafePacker)null, new UserScore("Doug", 100)));
+
+            Assert.Equal("packer", ex.ParamName);
+
+            ex = Assert.Throws<ArgumentNullException>(() => new Serialiser(typeof(UserScore)).Serialise((UnsafePacker)null, new UserScore("Doug", 100)));
+
+            Assert.Equal("packer", ex.ParamName);
+        }
+
         #region Helper
 
         private static T RoundTrip<T>(T before)

Dasher/Serialiser.cs

@@ -40,12 +40,16 @@ public Serialiser(DasherContext context = null)
 
         public void Serialise(Stream stream, T value)
         {
+            if (stream == null)
+                throw new ArgumentNullException(nameof(stream));
             using (var packer = new UnsafePacker(stream))
                 Serialise(packer, value);
         }
 
         public void Serialise(UnsafePacker packer, T value)
         {
+            if (packer == null)
+                throw new ArgumentNullException(nameof(packer));
             _action(packer, _context, value);
         }
 
@@ -71,12 +75,16 @@ public Serialiser(Type type, DasherContext context = null)
 
         public void Serialise(Stream stream, object value)
         {
+            if (stream == null)
+                throw new ArgumentNullException(nameof(stream));
             using (var packer = new UnsafePacker(stream))
                 Serialise(packer, value);
         }
 
         public void Serialise(UnsafePacker packer, object value)
         {
+            if (packer == null)
+                throw new ArgumentNullException(nameof(packer));
             _action(packer, _context, value);
         }