func TestCallbacks(t *testing.T) {
	type callback struct {
		name    string
		before  string
		after   string
		remove  bool
		replace bool
		err     string
		match   func(*gorm.DB) bool
		h       func(*gorm.DB)
	}

	datas := []struct {
		callbacks []callback
		err       string
		results   []string
	}{
		{
			callbacks: []callback{{h: c1}, {h: c2}, {h: c3}, {h: c4}, {h: c5}},

## The normal **FastAPI** app

Let's first see how the normal API app would look like before adding the callback.

It will have a *path operation* that will receive an `Invoice` body, and a query parameter `callback_url` that will contain the URL for the callback.

This part is pretty normal, most of the code is probably already familiar to you:

            projectsConfigured(":buildSrc", ":b")
            buildModelCreated()
            modelsCreated(":", ":a")
        }

        outputContains("Callback before root project 'root'")
        outputContains("Callback before project ':a'")
        outputContains("Callback before project ':b'")


        when:
        withIsolatedProjects()
        def model2 = runBuildAction(new FetchCustomModelForEachProject())

  override fun handle(callbacks: Array<Callback>) {
    for (callback in callbacks) {
      if (callback is PasswordCallback) {
        val console = System.console()

        if (console != null) {
          callback.password = console.readPassword(callback.prompt)
        } else {
          System.err.println(callback.prompt)
          callback.password = System.`in`.bufferedReader().readLine().toCharArray()

    void cancel();

    /**
     * @return current state of cancellation request before callback was added.
     */
    boolean addCallback(Runnable cancellationHandler);

    /**
     * Removes a callback called when cancellation request happens.
     *
     * @param cancellationHandler removed callback.
     */
    void removeCallback(Runnable cancellationHandler);

import mockwebserver3.MockWebServer
import org.junit.jupiter.api.Test

class DispatcherCleanupTest {
  @Test
  fun testFinish(server: MockWebServer) {
    val okhttp = OkHttpClient()
    val callback =
      object : Callback {
        override fun onFailure(
          call: Call,
          e: IOException,
        ) {}

        override fun onResponse(
          call: Call,
          response: Response,
        ) {

  private val source: BufferedSource,
  private val callback: Callback,
) {
  private var lastId: String? = null

  interface Callback {
    fun onEvent(
      id: String?,
      type: String?,
      data: String,
    )

    fun onRetryChange(timeMs: Long)
  }

  /**
   * Process the next event. This will result in a single call to [Callback.onEvent] *unless* the

@Implements(DnsResolver::class)
class ShadowDnsResolver {
  var responder: (Request) -> Unit = {
    it.callback.onAnswer(listOf(), 0)
  }

  data class Request(
    val network: Network?,
    val domain: String,
    val nsType: Int,
    val flags: Int,
    val callback: DnsResolver.Callback<List<InetAddress>>,
  )

  @Implementation
  fun query(
    network: Network?,
    domain: String,

  override fun query(
    hostname: String,
    callback: AsyncDns.Callback,
  ) {
    try {
      resolver.query(
        network,
        hostname,
        dnsClass.type,
        DnsResolver.FLAG_EMPTY,
        executor,
        null,
        object : DnsResolver.Callback<List<InetAddress>> {
          override fun onAnswer(
            addresses: List<InetAddress>,

interface AsyncDns {
  /**
   * Query DNS records for `hostname`, in the order they are received.
   */
  fun query(
    hostname: String,
    callback: Callback,
  )

  /**
   * Callback to receive results from the DNS Queries.
   */
  @ExperimentalOkHttpApi
  interface Callback {
    /**
     * Return addresses for a dns query for a single class of IPv4 (A) or IPv6 (AAAA).