Add test for nested arrays and objects

Author: xPaw

ValveKeyValue/ValveKeyValue.Test/Test Data/TextKV3/array_nested.kv3

@@ -0,0 +1,40 @@
+<!-- kv3 encoding:text:version{e21c7f3c-8a33-41c5-9977-a76d3a32aa0d} format:generic:version{7412167c-06e9-4698-aff2-e63eb59037e7} -->
+{
+	array = [
+		1,
+		2,
+		3,
+		{
+			array2 = [
+				4,
+				5,
+				6,
+				{
+					something = "something"
+					array3 = [
+						7,
+						8,
+						9,
+					]
+					test = "abc"
+				},
+				10,
+			]
+			test2 = "def"
+		},
+		"string",
+		11,
+		12,
+		[
+			13,
+			14,
+			15,
+			[
+				16,
+				17,
+				18,
+			],
+		],
+		19,
+	]
+}

ValveKeyValue/ValveKeyValue.Test/TextKV3/SerializationTestCase.cs

@@ -53,6 +53,27 @@ public void SerializesArray()
             Assert.That(text, Is.EqualTo(expected));
         }
 
+        [Test]
+        public void SerializesNestedArray()
+        {
+            var expected = TestDataHelper.ReadTextResource("TextKV3.array_nested.kv3");
+
+            var kv = KVSerializer.Create(KVSerializationFormat.KeyValues3Text);
+            var data = kv.Deserialize(expected);
+
+            string text;
+            using (var ms = new MemoryStream())
+            {
+                kv.Serialize(ms, data);
+
+                ms.Seek(0, SeekOrigin.Begin);
+                using var reader = new StreamReader(ms);
+                text = reader.ReadToEnd();
+            }
+
+            Assert.That(text, Is.EqualTo(expected));
+        }
+
         [Test]
         public void SerializesFlags()
         {