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

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

    // * The element with (index == from) should be kept.
    // * Everything with (index > from) has not been checked yet.

    // Check from the end of the list backwards (minimize expected cost of
    // moving elements when remove() is called). Stop before 'from' because
    // we already know that should be kept.
    for (int n = list.size() - 1; n > from; n--) {

                    .get());
            options.addOption(Option.builder(BATCH_MODE)
                    .longOpt("batch-mode")
                    .desc("Run in non-interactive mode. Alias for --non-interactive (kept for backwards compatability)")
                    .get());
            options.addOption(Option.builder()
                    .longOpt(NON_INTERACTIVE)
                    .desc("Run in non-interactive mode. Alias for --batch-mode")

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

    they could leak passwords and other authentication credentials to insecure
    logs.

 *  **WebSocket API now uses `RequestBody` and `ResponseBody` for messages.**
    This is a backwards-incompatible API change.

 *  **The DNS service is now pluggable.** In some situations this may be useful
    to manually prioritize specific IP addresses.

* For Deployment, ReplicaSet, and DaemonSet, selectors are now immutable when updating via the new `apps/v1beta2` API. For backward compatibility, selectors can still be changed when updating via `apps/v1beta1` or `extensions/v1beta1`. ([#50719](https://github.com/kubernetes/kubernetes/pull/50719), [@crimsonfaith91](https://github.com/crimsonfaith91))

  }

  /**
   * Either writes this request to [sink] or measures its content length. We have one method do
   * double-duty to make sure the counting and content are consistent, particularly when it comes
   * to awkward operations like measuring the encoded length of header strings, or the
   * length-in-digits of an encoded integer.
   */
  @Throws(IOException::class)
  private fun writeOrCountBytes(
    sink: BufferedSink?,

- Dropped the additional rule requirement (cronjobs/finalizers) for roles
  using kubectl create cronjobs to ensure backward compatibility. ([#124883](https://github.com/kubernetes/kubernetes/pull/124883), [@ardaguclu](https://github.com/ardaguclu))

   * Whenever an implementation uses `instanceof` on a parameter instance, the test has to know that
   * (so much for "black box") and try instances that both do and don't pass the check. The "don't"
   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {

 *   <li>Improved memory compactness and locality.
 *   <li>Can be queried without allocating garbage.
 *   <li>Access to {@code LongStream} features (like {@link LongStream#sum}) using {@code stream()}
 *       instead of the awkward {@code stream().mapToLong(v -> v)}.
 * </ul>
 *
 * <p>Disadvantages compared to {@code ImmutableList<Long>}:
 *
 * <ul>
 *   <li>Can't be passed directly to methods that expect {@code Iterable}, {@code Collection}, or