feat: add MCP HTTP server with JSON-RPC 2.0 transport

internal/mcp/server_test.go

@@ -0,0 +1,78 @@
+package mcp_test
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/mathiasbq/supervisor/internal/mcp"
+	"github.com/mathiasbq/supervisor/internal/registry"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func jsonBody(t *testing.T, v any) *bytes.Buffer {
+	t.Helper()
+	b, err := json.Marshal(v)
+	require.NoError(t, err)
+	return bytes.NewBuffer(b)
+}
+
+func TestMCPInitialize(t *testing.T) {
+	reg := registry.New()
+	srv := mcp.NewServer(reg)
+
+	req := httptest.NewRequest(http.MethodPost, "/mcp", jsonBody(t, map[string]any{
+		"jsonrpc": "2.0",
+		"id":      1,
+		"method":  "initialize",
+		"params":  map[string]any{},
+	}))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+
+	srv.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code)
+	var resp map[string]any
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &resp))
+	result := resp["result"].(map[string]any)
+	assert.Equal(t, "2024-11-05", result["protocolVersion"])
+}
+
+func TestMCPToolsList(t *testing.T) {
+	reg := registry.New()
+	srv := mcp.NewServer(reg)
+
+	req := httptest.NewRequest(http.MethodPost, "/mcp", jsonBody(t, map[string]any{
+		"jsonrpc": "2.0", "id": 2, "method": "tools/list", "params": map[string]any{},
+	}))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+	srv.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code)
+	var resp map[string]any
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &resp))
+	result := resp["result"].(map[string]any)
+	assert.NotNil(t, result["tools"])
+}
+
+func TestMCPUnknownMethod(t *testing.T) {
+	reg := registry.New()
+	srv := mcp.NewServer(reg)
+
+	req := httptest.NewRequest(http.MethodPost, "/mcp", jsonBody(t, map[string]any{
+		"jsonrpc": "2.0", "id": 3, "method": "unknown/method", "params": map[string]any{},
+	}))
+	req.Header.Set("Content-Type", "application/json")
+	rr := httptest.NewRecorder()
+	srv.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code)
+	var resp map[string]any
+	require.NoError(t, json.Unmarshal(rr.Body.Bytes(), &resp))
+	assert.NotNil(t, resp["error"])
+}