package main import (	"encoding/json"	"errors"	"fmt"	"net/http"	"testing") func TestErrorEnvelopeCarriesHTTPStatus(t *testing.T) {	raw := errorEnvelope("forbidden", "permission denied", http.StatusForbidden)	var env envelope	if errUnmarshal := json.Unmarshal(raw, &env); errUnmarshal != nil {		t.Fatalf("unmarshal envelope: %v", errUnmarshal)	}	if env.OK {		t.Fatalf("env.OK = true, want false")	}	if env.Error == nil {		t.Fatal("env.Error = nil, want non-nil")	}	if env.Error.HTTPStatus != http.StatusForbidden {		t.Fatalf("env.Error.HTTPStatus = %d, want %d", env.Error.HTTPStatus, http.StatusForbidden)	}} type mockStatusError struct {	status int	msg    string} func (m mockStatusError) Error() string   { return m.msg }func (m mockStatusError) StatusCode() int { return m.status } func TestErrorEnvelopeFromStatusError(t *testing.T) {	inner := mockStatusError{status: http.StatusTooManyRequests, msg: "rate limit exceeded"}	wrappedErr := fmt.Errorf("call upstream: %w", inner)	status := 0	type statusCoder interface{ StatusCode() int }	var sc statusCoder	if errors.As(wrappedErr, &sc) && sc != nil {		status = sc.StatusCode()	}	raw := errorEnvelope("rate_limit_error", wrappedErr.Error(), status)	var env envelope	if errUnmarshal := json.Unmarshal(raw, &env); errUnmarshal != nil {		t.Fatalf("unmarshal envelope: %v", errUnmarshal)	}	if env.Error == nil || env.Error.HTTPStatus != http.StatusTooManyRequests {		t.Fatalf("expected HTTPStatus %d, got %+v", http.StatusTooManyRequests, env.Error)	}}