then verify that requests were made as expected.

Because it exercises your full HTTP stack, you can be confident that you're
testing everything. You can even copy & paste HTTP responses from your real web
server to create representative test cases. Or test that your code survives in
awkward-to-reproduce situations like 500 errors or slow-loading responses.


### Example

    //
    // HttpUrl is quite lenient with what characters it accepts. In particular, characters like '{'
    // and '"' are permitted but unlikely to occur in real-world URLs. Unfortunately we can't just
    // lock it down due to URL templating: "http://{env}.{dc}.example.com".
    UrlComponentEncodingTester.newInstance()
      .nonPrintableAscii(Encoding.FORBIDDEN)

        )
        return
      }

      // This is a long-lived response. Cancel full-call timeouts.
      call?.timeout()?.cancel()

      // Replace the body with a stripped one so the callbacks can't see real data.
      val response = response.stripBody()

      val reader = ServerSentEventReader(body.source(), this)
      try {
        if (!canceled) {
          listener.onOpen(this, response)

import okhttp3.internal.http2.Http2.formatFlags
import okhttp3.internal.http2.Http2.frameLog
import okhttp3.internal.http2.Http2.frameLogWindowUpdate
import org.junit.jupiter.api.Test

class FrameLogTest {
  /** Real stream traffic applied to the log format.  */
  @Test
  fun exampleStream() {
    assertThat(frameLog(false, 0, 5, TYPE_SETTINGS, FLAG_NONE))
      .isEqualTo(">> 0x00000000     5 SETTINGS      ")

a fake `HostnameVerifier` or `X509TrustManager`.

Certificate Authorities
-----------------------

The above example uses a self-signed certificate. This is convenient for testing but not
representative of real-world HTTPS deployment. To get closer to that we can use `HeldCertificate`
to generate a trusted root certificate, an intermediate certificate, and a server certificate.

    val writer = Http2Writer(Buffer(), true)
    assertFailsWith<IllegalArgumentException> {
      writer.frameHeader(0, 16777216, Http2.TYPE_DATA, FLAG_NONE)
    }.also { expected ->
      // TODO: real max is based on settings between 16384 and 16777215
      assertThat(expected.message).isEqualTo("FRAME_SIZE_ERROR length > 16384: 16777216")
    }
  }

  @Test fun ackSettingsAppliesMaxFrameSize() {

// day : 2014-01-30 Charleston Road Registry Inc.
day

// dclk : 2014-11-20 Charleston Road Registry Inc.
dclk

// dds : 2015-05-07 Registry Services, LLC
dds

// deal : 2015-06-25 Amazon Registry Services, Inc.
deal

// dealer : 2014-12-22 Intercap Registry Inc.
dealer

// deals : 2014-05-22 Binky Moon, LLC
deals

// degree : 2014-03-06 Dog Beach, LLC
degree

2F18          ; mapped                 ; 535C          # 3.0  KANGXI RADICAL DIVINATION
2F19          ; mapped                 ; 5369          # 3.0  KANGXI RADICAL SEAL
2F1A          ; mapped                 ; 5382          # 3.0  KANGXI RADICAL CLIFF
2F1B          ; mapped                 ; 53B6          # 3.0  KANGXI RADICAL PRIVATE

   * This is like [toLowerCase] except that it does nothing if this contains any non-ASCII
   * characters. We want to avoid lower casing special chars like U+212A (Kelvin symbol) because
   * they can return ASCII characters that match real hostnames.
   */
  private fun String.asciiToLowercase(): String {
    return when {
      isAscii() -> lowercase(Locale.US) // This is an ASCII string.
      else -> this
    }
  }

import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.Tag
import org.junit.jupiter.api.Test

/**
 * Integration test to confirm that [TaskRunner] works with a real backend. Business logic is all
 * exercised by [TaskRunnerTest].
 *
 * This test is doing real sleeping with tolerances of 250 ms. Hopefully that's enough for even the
 * busiest of CI servers.
 */
@Tag("Slowish")
class TaskRunnerRealBackendTest {