/**
 * .what = the test runner currently executing the code
 * .why = enables isomorphic behavior between vitest and jest
 */
export type TestRunner = 'vitest' | 'jest';
/**
 * .what = reads which test runner is executing, or null where none is
 * .why = two callers need the same detection with OPPOSITE dispositions on absence:
 *        an isomorphic api shim must fail fast, while the unhooked notice must stay
 *        SILENT — a cli or a tsx one-off has no runner config to name, so a thrown
 *        error there would break a caller who did nothing wrong
 *
 * .note = this is the ONE place the two env keys are read. a second copy of these
 *         two lines is a second source of truth for "what is a runner", and the two
 *         would drift the day a third runner appears
 *
 * .note = vitest is checked first as it's more specific
 */
export declare const getOneTestRunner: () => TestRunner | null;
/**
 * .what = detects which test runner is currently executing
 * .why = enables runtime selection of test framework apis
 *
 * @throws UnexpectedCodePathError when no runner is in play
 */
export declare const detectTestRunner: () => TestRunner;
export declare const getTestRunner: () => TestRunner;
/**
 * .what = resets the cached runner (for testing only)
 * .why = allows tests to verify detection logic with different env states
 */
export declare const resetTestRunnerCache: () => void;