internal/jsonrpc2_v2: an updated jsonrpc2 library

Change-Id: I609173baa6842d33068a7e9596d54f03d89c5401
Reviewed-on: https://go-review.googlesource.com/c/tools/+/292169
Run-TryBot: Ian Cottrell <iancottrell@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Ian Cottrell <iancottrell@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

internal/jsonrpc2/wire_test.go

@@ -0,0 +1,118 @@
+// Copyright 2020 The Go MCP SDK Authors. All rights reserved.
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package jsonrpc2_test
+
+import (
+	"bytes"
+	"encoding/json"
+	"reflect"
+	"testing"
+
+	"github.com/modelcontextprotocol/go-sdk/internal/jsonrpc2"
+)
+
+func TestWireMessage(t *testing.T) {
+	for _, test := range []struct {
+		name    string
+		msg     jsonrpc2.Message
+		encoded []byte
+	}{{
+		name:    "notification",
+		msg:     newNotification("alive", nil),
+		encoded: []byte(`{"jsonrpc":"2.0","method":"alive"}`),
+	}, {
+		name:    "call",
+		msg:     newCall("msg1", "ping", nil),
+		encoded: []byte(`{"jsonrpc":"2.0","id":"msg1","method":"ping"}`),
+	}, {
+		name:    "response",
+		msg:     newResponse("msg2", "pong", nil),
+		encoded: []byte(`{"jsonrpc":"2.0","id":"msg2","result":"pong"}`),
+	}, {
+		name:    "numerical id",
+		msg:     newCall(1, "poke", nil),
+		encoded: []byte(`{"jsonrpc":"2.0","id":1,"method":"poke"}`),
+	}, {
+		// originally reported in #39719, this checks that result is not present if
+		// it is an error response
+		name: "computing fix edits",
+		msg:  newResponse(3, nil, jsonrpc2.NewError(0, "computing fix edits")),
+		encoded: []byte(`{
+		"jsonrpc":"2.0",
+		"id":3,
+		"error":{
+			"code":0,
+			"message":"computing fix edits"
+		}
+	}`),
+	}} {
+		b, err := jsonrpc2.EncodeMessage(test.msg)
+		if err != nil {
+			t.Fatal(err)
+		}
+		checkJSON(t, b, test.encoded)
+		msg, err := jsonrpc2.DecodeMessage(test.encoded)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(msg, test.msg) {
+			t.Errorf("decoded message does not match\nGot:\n%+#v\nWant:\n%+#v", msg, test.msg)
+		}
+	}
+}
+
+func newNotification(method string, params interface{}) jsonrpc2.Message {
+	msg, err := jsonrpc2.NewNotification(method, params)
+	if err != nil {
+		panic(err)
+	}
+	return msg
+}
+
+func newID(id interface{}) jsonrpc2.ID {
+	switch v := id.(type) {
+	case nil:
+		return jsonrpc2.ID{}
+	case string:
+		return jsonrpc2.StringID(v)
+	case int:
+		return jsonrpc2.Int64ID(int64(v))
+	case int64:
+		return jsonrpc2.Int64ID(v)
+	default:
+		panic("invalid ID type")
+	}
+}
+
+func newCall(id interface{}, method string, params interface{}) jsonrpc2.Message {
+	msg, err := jsonrpc2.NewCall(newID(id), method, params)
+	if err != nil {
+		panic(err)
+	}
+	return msg
+}
+
+func newResponse(id interface{}, result interface{}, rerr error) jsonrpc2.Message {
+	msg, err := jsonrpc2.NewResponse(newID(id), result, rerr)
+	if err != nil {
+		panic(err)
+	}
+	return msg
+}
+
+func checkJSON(t *testing.T, got, want []byte) {
+	// compare the compact form, to allow for formatting differences
+	g := &bytes.Buffer{}
+	if err := json.Compact(g, []byte(got)); err != nil {
+		t.Fatal(err)
+	}
+	w := &bytes.Buffer{}
+	if err := json.Compact(w, []byte(want)); err != nil {
+		t.Fatal(err)
+	}
+	if g.String() != w.String() {
+		t.Errorf("encoded message does not match\nGot:\n%s\nWant:\n%s", g, w)
+	}
+}