/**
 * What this package offers to tests alone.
 *
 * This has its own entry in the package's export map and no place in any
 * barrel, so that nothing outside a test reaches it by accident.
 */

import { freezePartialCauses } from "./builder/pattern.ts";
import type { Pattern } from "./builder/types.ts";

/**
 * Returns `pattern`, a pattern a test writes out as an object literal rather
 * than building with the builder, with its partial causes deep-frozen in place
 * the way the builder freezes those of every pattern it builds. The runtime
 * refuses a partial cause that is an object but not deep-frozen, so a literal
 * whose manifest or `$alias` bindings carry an object cause runs only once it
 * has been through here.
 */
export function patternLiteralForTestingOnly<T extends Pattern>(
  pattern: T,
): T {
  freezePartialCauses(pattern);
  return pattern;
}