Add tests for DateTime behaviour, fix typo (#84)

Fixes #63.

ValveKeyValue/ValveKeyValue.Test/KVDateTimeTestCase.cs

@@ -0,0 +1,42 @@
+using System;
+using System.IO;
+using NUnit.Framework;
+
+namespace ValveKeyValue.Test
+{
+    class KVDateTimeTestCase
+    {
+        [Test]
+        public void InvalidCast()
+        {
+            var obj = new KVObject("test", "some value that could be a date");
+            Assert.That(
+                () => obj.Value.ToDateTime(default),
+                Throws.InstanceOf<InvalidCastException>());
+        }
+
+        [Test]
+        public void DeserializeDateTimeNotSupported()
+        {
+            var obj = new KVObject("test", new[]
+            {
+                new KVObject("Value", "some value that could be a date")
+            });
+            using var ms = new MemoryStream();
+            var serializer = KVSerializer.Create(KVSerializationFormat.KeyValues1Text);
+
+            serializer.Serialize(ms, obj);
+            ms.Seek(0, SeekOrigin.Begin);
+
+            Assert.That(
+                () => serializer.Deserialize<SerializedType>(ms),
+                Throws.InstanceOf<NotSupportedException>()
+                .With.Message.EqualTo("Converting to DateTime is not supported. (key = Value, type = String)"));
+        }
+
+        class SerializedType
+        {
+            public DateTime Value { get;set; }
+        }
+    }
+}

ValveKeyValue/ValveKeyValue/KVObjectValue.cs

@@ -41,10 +41,7 @@ public override TypeCode GetTypeCode()
 
         public override char ToChar(IFormatProvider provider) => (char)Convert.ChangeType(value, typeof(char), provider);
 
-        public override DateTime ToDateTime(IFormatProvider provider)
-        {
-            throw new InvalidCastException("Casting to DateTime is not supported.");
-        }
+        public override DateTime ToDateTime(IFormatProvider provider) => throw new InvalidCastException("Casting to DateTime is not supported.");
 
         public override decimal ToDecimal(IFormatProvider provider) => (decimal)Convert.ChangeType(value, typeof(decimal), provider);
 

ValveKeyValue/ValveKeyValue/ObjectCopier.cs

@@ -55,7 +55,7 @@ public static TObject MakeObject<TObject>(KVObject keyValueObject, IObjectReflec
             else
             {
                 // TODO: For nullable types this typeof is not that useful
-                throw new NotSupportedException($"Convering to {typeof(TObject).Name} is not supported. (key = {keyValueObject.Name}, type = {keyValueObject.Value.ValueType})");
+                throw new NotSupportedException($"Converting to {typeof(TObject).Name} is not supported. (key = {keyValueObject.Name}, type = {keyValueObject.Value.ValueType})");
             }
         }
 
@@ -414,7 +414,6 @@ static bool CanConvertValueTo(Type type)
                 type == typeof(bool) ||
                 type == typeof(byte) ||
                 type == typeof(char) ||
-                // type == typeof(DateTime) || // TODO: Casting to DateTime (from int32) is not supported
                 type == typeof(decimal) ||
                 type == typeof(double) ||
                 type == typeof(float) ||