chore: import upstream snapshot with attribution

internal/event/testutil/testutil.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+// Package testutil holds test-only helpers shared across event subsystem tests.
+package testutil
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"net"
+	"sync"
+
+	"github.com/larksuite/cli/internal/event/transport"
+)
+
+// FakeTransport delegates to inner with a fixed addr, so tests can use t.TempDir paths.
+type FakeTransport struct {
+	addr     string
+	inner    transport.IPC
+	mu       sync.Mutex
+	cleaned  bool
+	cleanups int
+}
+
+func NewWrappedFake(inner transport.IPC, addr string) *FakeTransport {
+	return &FakeTransport{addr: addr, inner: inner}
+}
+
+func (t *FakeTransport) Listen(_ string) (net.Listener, error) {
+	return t.inner.Listen(t.addr)
+}
+
+func (t *FakeTransport) Dial(_ string) (net.Conn, error) {
+	return t.inner.Dial(t.addr)
+}
+
+func (t *FakeTransport) Address(_ string) string { return t.addr }
+
+func (t *FakeTransport) Cleanup(_ string) {
+	t.mu.Lock()
+	t.cleaned = true
+	t.cleanups++
+	t.mu.Unlock()
+	t.inner.Cleanup(t.addr)
+}
+
+func (t *FakeTransport) DidCleanup() bool {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	return t.cleaned
+}
+
+func (t *FakeTransport) CleanupCount() int {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	return t.cleanups
+}
+
+// StubAPIClient records the last call and returns Body or Err.
+type StubAPIClient struct {
+	Body string
+	Err  error
+
+	mu        sync.Mutex
+	GotMethod string
+	GotPath   string
+	GotBody   interface{}
+	Calls     int
+}
+
+func (s *StubAPIClient) CallAPI(_ context.Context, method, path string, body interface{}) (json.RawMessage, error) {
+	s.mu.Lock()
+	s.GotMethod = method
+	s.GotPath = path
+	s.GotBody = body
+	s.Calls++
+	s.mu.Unlock()
+	if s.Err != nil {
+		return nil, s.Err
+	}
+	if s.Body == "" {
+		return json.RawMessage("{}"), nil
+	}
+	return json.RawMessage(s.Body), nil
+}
+
+var ErrStubUnconfigured = errors.New("testutil.StubAPIClient: no body or err configured")