patterm/internal/mcp/protocol_test.go

package mcp

import (
	"encoding/json"
	"testing"
)

func TestInitializeReturnsCapabilities(t *testing.T) {
	s := &Server{}
	req := []byte(`{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"claude","version":"1.0"}}}`)
	resp := s.dispatch("", req)
	if resp == nil {
		t.Fatal("expected response for initialize")
	}
	var parsed struct {
		JSONRPC string                 `json:"jsonrpc"`
		ID      json.RawMessage        `json:"id"`
		Result  map[string]interface{} `json:"result"`
		Error   *struct {
			Code int `json:"code"`
		} `json:"error"`
	}
	if err := json.Unmarshal(resp, &parsed); err != nil {
		t.Fatalf("parse: %v\n%s", err, resp)
	}
	if parsed.Error != nil {
		t.Fatalf("initialize returned error: %+v", parsed.Error)
	}
	if parsed.Result["protocolVersion"] == nil {
		t.Fatalf("missing protocolVersion: %+v", parsed.Result)
	}
	caps, ok := parsed.Result["capabilities"].(map[string]interface{})
	if !ok {
		t.Fatalf("capabilities not object: %+v", parsed.Result)
	}
	if caps["tools"] == nil {
		t.Fatalf("tools capability missing: %+v", caps)
	}
}

func TestInitializedNotificationSuppressesResponse(t *testing.T) {
	s := &Server{}
	req := []byte(`{"jsonrpc":"2.0","method":"notifications/initialized"}`)
	resp := s.dispatch("", req)
	if resp != nil {
		t.Fatalf("notification produced a response: %s", resp)
	}
}

func TestToolsListReturnsConcreteSchemas(t *testing.T) {
	s := &Server{}
	req := []byte(`{"jsonrpc":"2.0","id":2,"method":"tools/list"}`)
	resp := s.dispatch("", req)
	if resp == nil {
		t.Fatal("expected response for tools/list")
	}
	var parsed struct {
		Result map[string]interface{} `json:"result"`
		Error  *struct {
			Code    int    `json:"code"`
			Message string `json:"message"`
		} `json:"error"`
	}
	if err := json.Unmarshal(resp, &parsed); err != nil {
		t.Fatalf("parse: %v\n%s", err, resp)
	}
	if parsed.Error != nil {
		t.Fatalf("tools/list returned error: %+v", parsed.Error)
	}
	tools, ok := parsed.Result["tools"].([]interface{})
	if !ok {
		t.Fatalf("tools not array: %+v", parsed.Result)
	}
	if len(tools) == 0 {
		t.Fatalf("expected at least one tool, got 0")
	}
	// Every tool must have name, description, and inputSchema with
	// `type=object` and a concrete `properties` object — `properties:
	// null` trips up strict MCP clients (claude in particular).
	for i, tool := range tools {
		entry, ok := tool.(map[string]interface{})
		if !ok {
			t.Fatalf("tool %d not object: %#v", i, tool)
		}
		if entry["name"] == "" || entry["name"] == nil {
			t.Fatalf("tool %d missing name: %#v", i, entry)
		}
		if entry["description"] == "" || entry["description"] == nil {
			t.Fatalf("tool %d missing description: %#v", i, entry)
		}
		schema, ok := entry["inputSchema"].(map[string]interface{})
		if !ok {
			t.Fatalf("tool %d inputSchema not object: %#v", i, entry)
		}
		if schema["type"] != "object" {
			t.Fatalf("tool %d schema type != object: %#v", i, schema)
		}
		props, ok := schema["properties"]
		if !ok {
			t.Fatalf("tool %s missing properties", entry["name"])
		}
		if _, ok := props.(map[string]interface{}); !ok {
			t.Fatalf("tool %s properties not object (got %T): %#v", entry["name"], props, props)
		}
	}
}

func TestPingReturnsEmptyObject(t *testing.T) {
	s := &Server{}
	req := []byte(`{"jsonrpc":"2.0","id":3,"method":"ping"}`)
	resp := s.dispatch("", req)
	if resp == nil {
		t.Fatal("expected response for ping")
	}
	var parsed struct {
		Result map[string]interface{} `json:"result"`
		Error  *struct{ Code int }    `json:"error"`
	}
	if err := json.Unmarshal(resp, &parsed); err != nil {
		t.Fatalf("parse: %v\n%s", err, resp)
	}
	if parsed.Error != nil {
		t.Fatalf("ping returned error: %+v", parsed.Error)
	}
	if parsed.Result == nil {
		t.Fatal("ping result missing")
	}
}