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

davvenjárga.no davvesiida.no day dazaifu.fukuoka.jp dc.us dclk dd-dns.de ddns.me ddns.net ddns5.com ddnsfree.com ddnsgeek.com ddnsking.com ddnslive.com ddnss.de ddnss.org ddr.museum dds de de.com de.cool de.eu.org de.gt de.ls de.md de.trendhosting.cloud de.us deal dealer deals deatnu.no debian.net deca.jp deci.jp decorativearts.museum dedibox.fr dedyn.io def.br definima.io definima.net degree delaware.museum delhi.in delivery dell dell-ogliastra.it dellogliastra.it delmenhorst.museum deloitte delta demo.datacenter.fi...

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
    }
  }