@ElementTypesAreNonnullByDefault
public abstract class Ticker {
  /** Constructor for use by subclasses. */
  protected Ticker() {}

  /** Returns the number of nanoseconds elapsed since this ticker's fixed point of reference. */
  public abstract long read();

  /**
   * A ticker that reads the current time using {@link System#nanoTime}.
   *
   * @since 10.0
   */
  public static Ticker systemTicker() {
    return SYSTEM_TICKER;
  }

  }

  public void testElapsed_notRunning() {
    ticker.advance(1);
    stopwatch.start();
    ticker.advance(4);
    stopwatch.stop();
    ticker.advance(9);
    assertEquals(4, stopwatch.elapsed(NANOSECONDS));
  }

  public void testElapsed_multipleSegments() {
    stopwatch.start();
    ticker.advance(9);
    stopwatch.stop();

    ticker.advance(16);

    stopwatch.start();

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Ticker;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * A Ticker whose value can be advanced programmatically in test.
 *
 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called:

import static com.google.common.base.Preconditions.checkNotNull;

import java.io.FilterWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;

/** @author Colin Decker */
public class TestWriter extends FilterWriter {

  private final TestOutputStream out;

  public TestWriter(TestOption... options) throws IOException {

import java.io.FilterWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;

/**
 * A char sink for testing that has configurable behavior.
 *
 * @author Colin Decker
 */
public class TestCharSink extends CharSink implements TestStreamSupplier {

  private final TestByteSink byteSink;

  public TestCharSink(TestOption... options) {
    this.byteSink = new TestByteSink(options);

import static com.google.common.hash.Hashing.ChecksumType.CRC_32;

import java.util.zip.Checksum;
import junit.framework.TestCase;

/**
 * Tests for ChecksumHashFunction.
 *
 * @author Colin Decker
 */
public class ChecksumHashFunctionTest extends TestCase {

  public void testCrc32_equalsChecksumValue() throws Exception {
    assertChecksum(CRC_32, "");
    assertChecksum(CRC_32, "Z");

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.EnumSet;

/**
 * Tests for the default implementations of {@code ByteSink} methods.
 *
 * @author Colin Decker
 */
public class ByteSinkTest extends IoTestCase {

  private final byte[] bytes = newPreFilledByteArray(10000);

  private TestByteSink sink;

  @Override
  protected void setUp() throws Exception {

import java.util.List;
import junit.framework.TestCase;

/**
 * @param <S> the source or sink type
 * @param <T> the data type (byte[] or String)
 * @param <F> the factory type
 * @author Colin Decker
 */
@AndroidIncompatible // TODO(b/230620681): Make this available (even though we won't run it).
public class SourceSinkTester<S, T, F extends SourceSinkFactory<S, T>> extends TestCase {

  static final String LOREM_IPSUM =

import static org.junit.Assert.assertThrows;

import java.io.IOException;
import java.nio.CharBuffer;
import junit.framework.TestCase;

/**
 * Tests for {@link CharSequenceReader}.
 *
 * @author Colin Decker
 */
public class CharSequenceReaderTest extends TestCase {

  public void testReadEmptyString() throws IOException {
    assertReadsCorrectly("");
  }

 * expected to contain as well as sub-suites for testing the {@code CharSource} view and {@code
 * slice()} views in the same way.
 *
 * @author Colin Decker
 */
@AndroidIncompatible // TODO(b/230620681): Make this available (even though we won't run it).
public class ByteSourceTester extends SourceSinkTester<ByteSource, byte[], ByteSourceFactory> {