chore: add C# meta method tests

tests/Lua.Tests/MetaTests.cs

@@ -0,0 +1,183 @@
+using Lua.Platforms;
+using Lua.Standard;
+using Lua.Tests.Helpers;
+using System.Globalization;
+
+namespace Lua.Tests;
+
+[LuaObject]
+partial class MetaFloat
+{
+    [LuaMember("value")] public double Value { get; set; }
+
+    [LuaMetamethod(LuaObjectMetamethod.Call)]
+    public static MetaFloat Create(LuaValue dummy, double value)
+    {
+        return new MetaFloat() { Value = value };
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Add)]
+    public static MetaFloat Add(MetaFloat a, MetaFloat b)
+    {
+        return new MetaFloat() { Value = a.Value + b.Value };
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Lt)]
+    public static bool Lt(MetaFloat a, MetaFloat b)
+    {
+        return a.Value < b.Value;
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Len)]
+    public static double Len(MetaFloat a)
+    {
+        return a.Value;
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.ToString)]
+    public override string ToString()
+    {
+        return Value.ToString(CultureInfo.InvariantCulture);
+    }
+}
+
+[LuaObject]
+partial class MetaAsyncFloat
+{
+    [LuaMember("value")] public double Value { get; set; }
+
+    [LuaMetamethod(LuaObjectMetamethod.Call)]
+    public static async Task<MetaFloat> Create(LuaValue dummy, double value)
+    {
+        await Task.Delay(1);
+        return new MetaFloat() { Value = value };
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Add)]
+    public static async Task<MetaFloat> Add(MetaFloat a, MetaFloat b)
+    {
+        await Task.Delay(1);
+        return new MetaFloat() { Value = a.Value + b.Value };
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Lt)]
+    public static async Task<bool> Lt(MetaFloat a, MetaFloat b)
+    {
+        await Task.Delay(1);
+        return a.Value < b.Value;
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.Len)]
+    public static async Task<double> Len(MetaFloat a)
+    {
+        await Task.Delay(1);
+        return a.Value;
+    }
+
+    [LuaMetamethod(LuaObjectMetamethod.ToString)]
+    public override string ToString()
+    {
+        return Value.ToString(CultureInfo.InvariantCulture);
+    }
+}
+
+public class MetaTests
+{
+    const string TestFloatScript = """
+                                   local a = MetaFloat(10)
+                                   local b = MetaFloat(20)
+                                   local function test(x,y)
+                                     local z = x + y
+                                     local v = z.value
+                                     local len, str = #z, tostring(z)
+                                     return v, y > x ,len, str
+                                   end
+                                   local v, comp, len, str = test(a,b)
+                                   assert(v == 30)
+                                   assert(comp == true)
+                                   assert(len == 30)
+                                   assert(str == "30")
+                                   local c = a + b
+                                   return c.value, a < b,#c, tostring(c)
+                                   """;
+
+    const string TestIndexScript = """
+                                   local obj = setmetatable({}, {__index = getindentityMethod})
+                                   local a
+                                   local b = 1
+                                   local c =obj
+                                   a = obj:getindentity()
+                                   local d = obj.getindentity(obj)
+                                   print(d)
+                                   assert(a == obj)
+                                   assert(b == 1)
+                                   assert(obj == c)
+                                   assert(d == c)
+                                   """;
+
+    [Test]
+    public async Task TestMetaFloat()
+    {
+        var lua = LuaState.Create();
+        lua.OpenBasicLibrary();
+        lua.Environment["MetaFloat"] = new MetaFloat();
+        var result = await lua.DoStringAsync(TestFloatScript);
+        Assert.That(result.Length, Is.EqualTo(4));
+        Assert.That(result[0].Read<double>(), Is.EqualTo(30));
+        Assert.That(result[1].Read<bool>(), Is.EqualTo(true));
+        Assert.That(result[2].Read<double>(), Is.EqualTo(30));
+        Assert.That(result[3].Read<string>(), Is.EqualTo("30"));
+    }
+
+    [Test]
+    public async Task TestMetaAsyncFloat()
+    {
+        var lua = LuaState.Create();
+        lua.OpenBasicLibrary();
+        lua.Environment["MetaFloat"] = new MetaAsyncFloat();
+
+        var result = await lua.DoStringAsync(TestFloatScript);
+        Assert.That(result.Length, Is.EqualTo(4));
+        Assert.That(result[0].Read<double>(), Is.EqualTo(30));
+        Assert.That(result[1].Read<bool>(), Is.EqualTo(true));
+        Assert.That(result[2].Read<double>(), Is.EqualTo(30));
+        Assert.That(result[3].Read<string>(), Is.EqualTo("30"));
+    }
+
+    [Test]
+    public async Task TestMetaIndex()
+    {
+        var lua = LuaState.Create(LuaPlatform.Default with{StandardIO = new TestStandardIO()}) ;
+        lua.OpenBasicLibrary();
+        
+        lua.Environment["getindentityMethod"] = new LuaFunction("getindentity", (context, ct) =>
+        {
+            var obj = context.GetArgument(0);
+            return new(context.Return(new LuaFunction("getIndexed", 
+                (ctx, ct2) =>
+                    new(ctx.Return(obj)))));
+        });
+
+
+        var result = await lua.DoStringAsync(TestIndexScript);
+    }
+
+    [Test]
+    public async Task TestMetaIndexAsync()
+    {
+        var lua = LuaState.Create(LuaPlatform.Default with{StandardIO = new TestStandardIO()}) ;
+        lua.OpenBasicLibrary();
+
+
+        lua.Environment["getindentityMethod"] = new LuaFunction("getindentity", async (context, ct) =>
+        {
+            var obj = context.GetArgument(0);
+            await Task.Delay(1);
+            return (context.Return(new LuaFunction("getIndexed", (ctx, ct2)
+                => new(ctx.Return(obj)))));
+        });
+
+
+        var result = await lua.DoStringAsync(TestIndexScript);
+    }
+}