Highlight JSON, TSCN and scenario fields across editor tools

tests/SchemaFieldControlTests.cs

@@ -0,0 +1,42 @@
+namespace Cthangover.Tools.Tests
+{
+    using System.Text.Json;
+    using System.Text.Json.Nodes;
+    using Cthangover.Core.Mods.Testing;
+    using Cthangover.Mods.Schemas;
+    using Cthangover.Tools.Schemas;
+    using Godot;
+
+    /// <summary>JSON schema fields preserve structured values through their highlighted multiline editor.</summary>
+    public class SchemaFieldControlTests
+    {
+        [ModTest("schema/json_field_roundtrip")]
+        static void JsonFieldRoundtrip(ModTestContext ctx)
+        {
+            var parent = new VBoxContainer();
+            ((SceneTree)Engine.GetMainLoop()).Root.AddChild(parent);
+            try
+            {
+                var field = new SchemaFieldControl(parent, new FieldSchema { Key = "Extra", Type = "json" }, null);
+                ModAssert.True(field.Editor is CodeEdit, "JSON field has a multiline code editor");
+                var code = (CodeEdit)field.Editor;
+                ModAssert.True(code.SyntaxHighlighter != null, "JSON field has syntax highlighting");
+                var original = new JsonObject
+                {
+                    ["text"] = "Unicode text: \u041f\u0440\u0438\u0432\u0435\u0442",
+                    ["active"] = true,
+                    ["nested"] = new JsonArray(1, null, 3),
+                };
+                field.Value = JsonSerializer.Serialize(original, new JsonSerializerOptions { WriteIndented = true });
+                var restored = JsonNode.Parse(field.Value);
+                ModAssert.Equal(original["text"].GetValue<string>(), restored["text"].GetValue<string>(), "text survives the field");
+                ModAssert.True(restored["active"].GetValue<bool>(), "boolean survives the field");
+                ModAssert.Equal(3, restored["nested"].AsArray().Count, "array survives the field");
+                ModAssert.True(restored["nested"][1] == null, "null survives the field");
+                code.Text = "{\n  \"number\": 42\n}";
+                ModAssert.Equal(42, JsonNode.Parse(field.Value)["number"].GetValue<int>(), "edited JSON is returned by the form");
+            }
+            finally { parent.Free(); }
+        }
+    }
+}