/**
 * Mock WebSocket for testing MixerConnection without a real network connection.
 * Implements the subset of the WebSocket API that rxjs/webSocket relies on
 * (direct onopen/onclose/onmessage/onerror handlers, not addEventListener).
 *
 * Pass as `webSocketCtor` in SoundcraftUIOptions to inject it.
 * Use `simulateOpen()`, `simulateMessage()`, or `simulateClose()`
 * to drive the connection lifecycle from tests.
 */
export declare class MockWebSocket {
    static readonly CONNECTING = 0;
    static readonly OPEN = 1;
    static readonly CLOSING = 2;
    static readonly CLOSED = 3;
    readonly CONNECTING = 0;
    readonly OPEN = 1;
    readonly CLOSING = 2;
    readonly CLOSED = 3;
    url: string;
    readyState: number;
    binaryType: string;
    onopen: ((event: Event) => void) | null;
    onclose: ((event: Event) => void) | null;
    onmessage: ((event: MessageEvent) => void) | null;
    onerror: ((event: Event) => void) | null;
    send: import('vitest').Mock<import('@vitest/spy').Procedure>;
    close: import('vitest').Mock<() => void>;
    /**
     * Creates a subclass that calls `onCapture` with each new instance.
     * Use this to get a reference to the WebSocket created internally by rxjs.
     */
    static withCapture(onCapture: (instance: MockWebSocket) => void): {
        new (url: string): {
            readonly CONNECTING: 0;
            readonly OPEN: 1;
            readonly CLOSING: 2;
            readonly CLOSED: 3;
            url: string;
            readyState: number;
            binaryType: string;
            onopen: ((event: Event) => void) | null;
            onclose: ((event: Event) => void) | null;
            onmessage: ((event: MessageEvent) => void) | null;
            onerror: ((event: Event) => void) | null;
            send: import('vitest').Mock<import('@vitest/spy').Procedure>;
            close: import('vitest').Mock<() => void>;
            addEventListener(): void;
            removeEventListener(): void;
            simulateOpen(): void;
            simulateMessage(data: string): void;
            simulateClose(): void;
        };
        readonly CONNECTING: 0;
        readonly OPEN: 1;
        readonly CLOSING: 2;
        readonly CLOSED: 3;
        withCapture(onCapture: (instance: MockWebSocket) => void): /*elided*/ any;
    };
    constructor(url: string);
    addEventListener(): void;
    removeEventListener(): void;
    simulateOpen(): void;
    simulateMessage(data: string): void;
    simulateClose(): void;
}