import type { Pool, PoolClient } from 'pg';
/**
 * Execute a function within an isolated database transaction
 * Automatically rolls back after execution to prevent data leakage between tests
 *
 * @param pool - PostgreSQL connection pool
 * @param fn - Async function to execute within transaction
 * @returns Promise resolving to function result
 *
 * @example
 * ```typescript
 * it('should create entity', () =>
 *   withTestTransaction(pool, async (client) => {
 *     const result = await ensureFinancialEntity(client, {...});
 *     expect(result.id).toBeDefined();
 *   })
 * );
 * ```
 */
export declare function withTestTransaction<T>(pool: Pool, fn: (client: PoolClient) => Promise<T>): Promise<T>;
/**
 * Execute multiple test functions in parallel, each in its own isolated transaction
 * Useful for testing concurrent access patterns
 *
 * @param pool - PostgreSQL connection pool
 * @param fns - Array of async functions to execute concurrently
 * @returns Promise resolving to array of results
 *
 * @example
 * ```typescript
 * const [result1, result2] = await withConcurrentTransactions(pool, [
 *   async (client) => ensureFinancialEntity(client, params),
 *   async (client) => ensureFinancialEntity(client, params),
 * ]);
 * ```
 */
export declare function withConcurrentTransactions<T>(pool: Pool, fns: Array<(client: PoolClient) => Promise<T>>): Promise<T[]>;