package api

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
)

func TestWriteErr_EmitsJSONEnvelope(t *testing.T) {
	w := httptest.NewRecorder()
	writeErr(w, http.StatusBadRequest, "bad_request", "field x required")

	if w.Code != http.StatusBadRequest {
		t.Errorf("status = %d, want 400", w.Code)
	}
	if got := w.Header().Get("Content-Type"); got != "application/json" {
		t.Errorf("content-type = %q, want application/json", got)
	}
	var body struct {
		Error struct {
			Code    string `json:"code"`
			Message string `json:"message"`
		} `json:"error"`
	}
	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v\nbody=%s", err, w.Body.String())
	}
	if body.Error.Code != "bad_request" || body.Error.Message != "field x required" {
		t.Errorf("body = %+v", body)
	}
}
