awkward-to-reproduce situations like 500 errors or slow-loading responses.


### Example

Use MockWebServer the same way that you use mocking frameworks like
[Mockito](https://github.com/mockito/mockito):

1. Script the mocks.
2. Run application code.
3. Verify that the expected requests were made.

Here's a complete example:

```java
public void test() throws Exception {

  fun matches(header: DerHeader): Boolean

  /**
   * Returns a value from this adapter.
   *
   * This must always return a value, though it doesn't necessarily need to consume data from
   * [reader]. For example, if the reader's peeked tag isn't readable by this adapter, it may return
   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,

### EventListener.Factory

In the preceding example we used a field, `callStartNanos`, to track the elapsed time of each event. This is handy, but it won’t work if multiple calls are executing concurrently. To accommodate this, use a `Factory` to create a new `EventListener` instance for each `Call`. This allows each listener to keep call-specific state.

import org.apache.hc.core5.http.ProtocolVersion
import org.junit.Assert
import org.junit.Test

/**
 * Simplified from
 * https://hc.apache.org/httpcomponents-client-5.0.x/httpclient5/examples/AsyncClientTlsAlpn.java
 *
 * Mainly intended to verify behaviour of popular clients across Android versions, similar
 * to observing Firefox or Chrome browser behaviour.
 */
class ApacheHttpClientHttp2Test {
  @Test

package okhttp3.sample;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import java.security.KeyStore;
import java.security.SecureRandom;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;
import okhttp3.mockwebserver.Dispatcher;

      CertificatePinner.Builder()
        .add("*.example.com", certA1Sha256Pin)
        .add("a.example.com", certB1Sha256Pin)
        .add("b.example.com", certC1Sha256Pin)
        .build()

    val expectedPins =
      listOf(
        Pin("*.example.com", certA1Sha256Pin),
        Pin("a.example.com", certB1Sha256Pin),
      )
    assertThat(certificatePinner.findMatchingPins("a.example.com")).isEqualTo(expectedPins)
  }

  @Test

    //    For example, *.example.com is permitted, while *a.example.com, a*.example.com,
    //    a*b.example.com, a.*.example.com are not permitted.
    // 2. Asterisk (*) cannot match across domain name labels.
    //    For example, *.example.com matches test.example.com but does not match
    //    sub.test.example.com.

      listOf(
        "Parsing: <http://example\t.\norg> against <http://example.org/foo/bar>",
        "Parsing: <http://f:0/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:00000000000000/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:\n/c> against <http://example.org/foo/bar>",
        "Parsing: <http://f:999999/c> against <http://example.org/foo/bar>",

import javax.security.auth.callback.UnsupportedCallbackException
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.internal.SuppressSignatureCheck
import okhttp3.internal.platform.Platform

/**
 * Example of using a hardware key to perform client auth.
 * Prefer recent JDK builds, and results are temperamental to slight environment changes.
 * Different instructions and configuration may be required for other hardware devices.
 *

 *    to use `H2_PRIOR_KNOWLEDGE` but the URL's scheme is `https:`.
 *  * Preemptive proxy authentication failed.
 *
 * Planning failures are not necessarily fatal. For example, even if we can't DNS lookup the first
 * proxy in a list, looking up a subsequent one may succeed.
 */
internal class FailedPlan(e: Throwable) : RoutePlanner.Plan {