def slow_sync_stream():
    yield {"n": 1}
    time.sleep(0.3)
    yield {"n": 2}


def test_keepalive_ping_async(monkeypatch: pytest.MonkeyPatch):
    monkeypatch.setattr(fastapi.routing, "_PING_INTERVAL", 0.05)
    with TestClient(keepalive_app) as c:
        response = c.get("/slow-async")
    assert response.status_code == 200
    text = response.text

# Keep-alive comment, per the SSE spec recommendation
KEEPALIVE_COMMENT = b": ping\n\n"

# Seconds between keep-alive pings when a generator is idle.
# Private but importable so tests can monkeypatch it.

     * [will fail with an IOException][java.io.IOException].
     *
     * The default value of 0 disables client-initiated pings.
     */
    fun pingInterval(
      interval: Long,
      unit: TimeUnit,
    ) = apply {
      pingInterval = checkDuration("interval", interval, unit)
    }

    /**
     * Sets the interval between HTTP/2 and web socket pings initiated by this client. Use this to

    closeWebSockets(webSocket, server)
  }

  @Test
  @Throws(Exception::class)
  fun clientPingsServerOnInterval() {
    client =
      client
        .newBuilder()
        .pingInterval(Duration.ofMillis(500))
        .build()
    webServer.enqueue(
      MockResponse
        .Builder()
        .webSocketUpgrade(serverListener)
        .build(),
    )
    val webSocket = newWebSocket()

    builder = builder.readTimeout(Duration.ofSeconds(0L))
    builder = builder.writeTimeout(0L, TimeUnit.SECONDS)
    builder = builder.writeTimeout(Duration.ofSeconds(0L))
    builder = builder.pingInterval(0L, TimeUnit.SECONDS)
    builder = builder.pingInterval(Duration.ofSeconds(0L))
    builder = builder.proxy(Proxy.NO_PROXY)
    builder = builder.proxySelector(NullProxySelector)
    builder = builder.cookieJar(CookieJar.NO_COOKIES)

	public final fun networkInterceptors ()Ljava/util/List;
	public final fun pingInterval (JLjava/util/concurrent/TimeUnit;)Lokhttp3/OkHttpClient$Builder;
	public final fun pingInterval (Ljava/time/Duration;)Lokhttp3/OkHttpClient$Builder;
	public final fun pingInterval-LRDsOJo (J)Lokhttp3/OkHttpClient$Builder;
	public final fun protocols (Ljava/util/List;)Lokhttp3/OkHttpClient$Builder;

	public final fun networkInterceptors ()Ljava/util/List;
	public final fun pingInterval (JLjava/util/concurrent/TimeUnit;)Lokhttp3/OkHttpClient$Builder;
	public final fun pingInterval (Ljava/time/Duration;)Lokhttp3/OkHttpClient$Builder;
	public final fun pingInterval-LRDsOJo (J)Lokhttp3/OkHttpClient$Builder;
	public final fun protocols (Ljava/util/List;)Lokhttp3/OkHttpClient$Builder;

      .isEqualTo(1)
  }

  @Test
  fun pingsTransmitted() {
    // Ping every 500 ms, starting at 500 ms.
    client =
      client
        .newBuilder()
        .pingInterval(Duration.ofMillis(500))
        .build()

    // Delay the response to give 1 ping enough time to be sent and replied to.
    server.enqueue(
      MockResponse
        .Builder()

from fastapi.exceptions import (
    EndpointContext,
    FastAPIError,
    RequestValidationError,
    ResponseValidationError,
    WebSocketRequestValidationError,
)
from fastapi.sse import (
    _PING_INTERVAL,
    KEEPALIVE_COMMENT,
    EventSourceResponse,
    ServerSentEvent,
    format_sse_event,
)
from fastapi.types import DecoratedCallable, IncEx
from fastapi.utils import (
    create_model_field,