import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
import java.util.Set;
import junit.framework.AssertionFailedError;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit tests for {@link EqualsTester}.
 *
 * @author Jim McMaster
 */
@GwtCompatible

Na verdade, todos (ou a maioria) dos frameworks web funcionam da mesma forma.

Você nunca chama essas funções diretamente. Elas são chamadas pelo framework utilizado (nesse caso, **FastAPI**).

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.SortedMap;
import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a NavigableMap
 * implementation.
 */
@GwtIncompatible

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Abstract test case parent for anything implementing {@link ListenableFuture}. Tests the two get
 * methods and the addListener method.
 *

import static org.junit.Assert.assertThrows;

import com.google.common.collect.Lists;
import java.util.List;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeoutException;
import junit.framework.TestCase;

/**
 * Tests for {@link AbstractIdleService}.
 *
 * @author Chris Nokleberg
 * @author Ben Yu
 */
public class AbstractIdleServiceTest extends TestCase {
  public void testStart() {

import java.util.NoSuchElementException;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import junit.framework.AssertionFailedError;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible(emulated = true)

import com.google.common.testing.SerializableTester;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import junit.framework.TestSuite;

/**
 * Creates, based on your criteria, a JUnit test suite that exhaustively tests a List
 * implementation.
 *
 * @author George van den Driessche
 */
@GwtIncompatible

import com.google.common.cache.TestingRemovalListeners.CountingRemovalListener;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import java.lang.ref.WeakReference;
import junit.framework.TestCase;

/**
 * Tests of basic {@link LoadingCache} operations with all possible combinations of key & value
 * strengths.
 *
 * @author mike nonemacher
 */
public class CacheReferencesTest extends TestCase {

import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.HashSet;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Base test case class for I/O tests.
 *
 * @author Chris Nokleberg
 * @author Colin Decker
 */

import com.google.common.testing.NullPointerTester;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.Locale;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import junit.framework.TestCase;

/**
 * Tests for ThreadFactoryBuilder.
 *
 * @author Kurt Alfred Kluever
 * @author Martin Buchholz
 */
public class ThreadFactoryBuilderTest extends TestCase {