ClawdDotNet/tests/ClawdDotNet.Core.Tests/Api/ChatMessageSerializationTests.cs

using System.Text.Json;
using ClawdDotNet.Core.Api.Models;
using Shouldly;

namespace ClawdDotNet.Core.Tests.Api;

public sealed class ChatMessageSerializationTests
{
    private static string Serialize(ChatMessage m) => JsonSerializer.Serialize(m);
    private static ChatMessage Deserialize(string json) => JsonSerializer.Deserialize<ChatMessage>(json)!;

    // ═══════════════════════════════════════════════════════════
    //  Standard format
    // ═══════════════════════════════════════════════════════════

    [Fact]
    public void Ohne_Breakpoint_bleibt_der_Inhalt_ein_einfacher_String()
    {
        var json = Serialize(ChatMessage.User("Hallo"));

        json.ShouldBe("""{"role":"user","content":"Hallo"}""");
    }

    [Fact]
    public void Nullwerte_werden_weggelassen()
    {
        var json = Serialize(ChatMessage.Assistant("Antwort"));

        json.ShouldNotContain("tool_calls");
        json.ShouldNotContain("tool_call_id");
    }

    [Fact]
    public void ToolAntwort_traegt_ihre_ToolCallId()
    {
        var json = Serialize(ChatMessage.ToolResponse("call_42", "Ergebnis"));

        json.ShouldBe("""{"role":"tool","content":"Ergebnis","tool_call_id":"call_42"}""");
    }

    [Fact]
    public void AssistantMitToolCalls_serialisiert_die_Aufrufe()
    {
        var msg = ChatMessage.AssistantWithToolCalls([
            new ToolCall { Id = "c1", Function = new ToolCallFunction { Name = "FileRW", Arguments = "{}" } }
        ]);

        var json = Serialize(msg);

        json.ShouldContain("tool_calls");
        json.ShouldContain("FileRW");
        json.ShouldNotContain("\"content\"", Case.Sensitive);
    }

    // ═══════════════════════════════════════════════════════════
    //  Cache-Breakpoint
    // ═══════════════════════════════════════════════════════════

    [Fact]
    public void Mit_Breakpoint_wird_der_Inhalt_zum_Block_mit_cache_control()
    {
        var msg = ChatMessage.System("Du bist ein Agent.");
        msg.CacheBreakpoint = true;

        var json = Serialize(msg);

        json.ShouldBe(
            """{"role":"system","content":[{"type":"text","text":"Du bist ein Agent.","cache_control":{"type":"ephemeral"}}]}""");
    }

    [Fact]
    public void Der_Breakpoint_selbst_wird_nicht_als_Feld_serialisiert()
    {
        var msg = ChatMessage.User("Text");
        msg.CacheBreakpoint = true;

        Serialize(msg).ShouldNotContain("CacheBreakpoint", Case.Insensitive);
    }

    // ═══════════════════════════════════════════════════════════
    //  Deserialization: both formats
    // ═══════════════════════════════════════════════════════════

    [Fact]
    public void Inhalt_als_String_wird_gelesen()
    {
        var msg = Deserialize("""{"role":"assistant","content":"Antwort"}""");

        msg.Role.ShouldBe("assistant");
        msg.Content.ShouldBe("Antwort");
    }

    [Fact]
    public void Inhalt_als_Blockarray_wird_gelesen()
    {
        // This is what a persisted context written with a breakpoint looks like.
        var msg = Deserialize(
            """{"role":"system","content":[{"type":"text","text":"Prompt","cache_control":{"type":"ephemeral"}}]}""");

        msg.Content.ShouldBe("Prompt");
    }

    [Fact]
    public void Mehrere_Textbloecke_werden_zusammengefuehrt()
    {
        var msg = Deserialize(
            """{"role":"user","content":[{"type":"text","text":"Teil A"},{"type":"text","text":" Teil B"}]}""");

        msg.Content.ShouldBe("Teil A Teil B");
    }

    [Fact]
    public void Fehlender_Inhalt_wird_zu_null()
    {
        var msg = Deserialize("""{"role":"assistant","tool_calls":[]}""");

        msg.Content.ShouldBeNull();
    }

    [Fact]
    public void Unbekannte_Felder_stoeren_nicht()
    {
        var msg = Deserialize("""{"role":"user","content":"Text","reasoning":"…","annotations":[1,2]}""");

        msg.Content.ShouldBe("Text");
    }

    [Fact]
    public void RoundTrip_erhaelt_alle_Felder()
    {
        var original = ChatMessage.ToolResponse("call_7", "Das Ergebnis");

        var restored = Deserialize(Serialize(original));

        restored.Role.ShouldBe("tool");
        restored.Content.ShouldBe("Das Ergebnis");
        restored.ToolCallId.ShouldBe("call_7");
    }

    [Fact]
    public void RoundTrip_erhaelt_Umlaute_und_Emoji()
    {
        var original = ChatMessage.User("Grüße aus München 🦀 — größer & schöner");

        var restored = Deserialize(Serialize(original));

        restored.Content.ShouldBe("Grüße aus München 🦀 — größer & schöner");
    }
}