[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
```java
public void test() throws Exception {
  // Create a MockWebServer. These are lean enough that you can create a new
  // instance for every unit test.
  MockWebServer server = new MockWebServer();

  // Schedule some responses.

  @CanIgnoreReturnValue
  public EquivalenceTester<T> test() {
    for (int run = 0; run < REPETITIONS; run++) {
      testItems();
      delegate.test();
    }
    return this;
  }

  private void testItems() {
    for (T item : items) {
      /*
       * TODO(cpovirk): consider no longer running these equivalent() tests on every Equivalence,
       * since the Equivalence base type now implements this logic itself

        }
        getSession().ifPresent(session -> session.removeAttribute(INVALID_OLD_PASSWORD));
        return redirect(ProfileAction.class);
    }

    private void validatePasswordForm(final PasswordForm form, final VaErrorHook validationErrorLambda) {
        validate(form, messages -> {}, validationErrorLambda);

        if (!form.password.equals(form.confirmPassword)) {

  int size;

  @Param({"2", "20"})
  int nonAlphaRatio; // one non-alpha char per this many chars

  @Param boolean noWorkToDo;

  Random random;
  String testString;

  @BeforeExperiment
  void setUp() {
    random = new Random(0xdeadbeef); // fix the seed so results are comparable across runs

    int nonAlpha = size / nonAlphaRatio;
    int alpha = size - nonAlpha;

  @Param({"0", "1", "16", "32", "100"})
  int componentLength;

  private Iterable<String> components;

  @BeforeExperiment
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  void setUp() {
    String component = Strings.repeat("a", componentLength);
    String[] raw = new String[count];
    Arrays.fill(raw, component);
    components = Arrays.asList(raw);
  }

  @Param Topology topology;

  @Param({"1", "100", "10000", "1000000"})
  int size;

  @Param Traversal traversal;

  @Param({"1234"})
  SpecialRandom rng;

  @BeforeExperiment
  void setUp() {
    this.view = traversal.view(topology.createTree(size, rng).get(), VIEWER);
  }

  @Benchmark
  int traversal(int reps) {
    int tmp = 0;

    for (int i = 0; i < reps; i++) {

              "net",
              "primitives",
              "reflect",
              "util.concurrent",
              "xml")
          .transform("com.google.common."::concat)
          .toSet();

  public void testClassesHaveOverrides() throws Exception {
    for (ClassInfo info : ClassPath.from(getClass().getClassLoader()).getAllClasses()) {
      if (!GUAVA_PACKAGES.contains(info.getPackageName())) {
        continue;
      }

import org.jspecify.annotations.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible
@NullMarked
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {
    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(

    return super.add(o);
  }

  @Override
  public boolean addAll(Collection<? extends E> c) {
    assertTrue(Thread.holdsLock(mutex));
    return super.addAll(c);
  }

  @Override
  public void clear() {
    assertTrue(Thread.holdsLock(mutex));
    super.clear();
  }

  @Override
  public boolean contains(@Nullable Object o) {
    assertTrue(Thread.holdsLock(mutex));
    return super.contains(o);
  }

    /* for doNetEnum and doFindFirstNext */
    int status;
    int numEntries;
    FileEntry[] results;

    SmbComTransactionResponse() {
        txn_buf = null;
    }

    @Override
    void reset() {
        super.reset();
        bufDataStart = 0;
        isPrimary = hasMore = true;
        parametersDone = dataDone = false;
    }

    @Override
    public boolean hasMoreElements() {