import { AbstractTTSClient } from "../core/abstract-tts";
import type { SpeakOptions, UnifiedVoice, WordBoundaryCallback } from "../types";
/**
 * Mock TTS client for testing
 */
export declare class MockTTSClient extends AbstractTTSClient {
    /**
     * Get available voices (internal implementation)
     * @returns Promise resolving to an array of unified voice objects
     */
    protected _getVoices(): Promise<UnifiedVoice[]>;
    /**
     * Convert text to audio bytes
     * @param _text Text to synthesize
     * @param _options Synthesis options
     * @returns Promise resolving to audio bytes
     */
    synthToBytes(_text: string, _options?: SpeakOptions): Promise<Uint8Array>;
    /**
     * Convert text to audio stream
     * @param text Text to synthesize
     * @param options Synthesis options
     * @returns Promise resolving to audio stream
     */
    synthToBytestream(text: string, options?: SpeakOptions): Promise<ReadableStream<Uint8Array> | {
        audioStream: ReadableStream<Uint8Array>;
        wordBoundaries: Array<{
            text: string;
            offset: number;
            duration: number;
        }>;
    }>;
    /**
     * Start playback with word boundary callbacks
     * @param text Text to speak
     * @param callback Callback function for word boundaries
     * @param _options Synthesis options
     */
    startPlaybackWithCallbacks(text: string, callback: WordBoundaryCallback, _options?: SpeakOptions): Promise<void>;
}