assertEquals(-1, counter.read(new byte[30]));
    assertEquals(20, counter.getCount());
  }

  @SuppressWarnings("CheckReturnValue") // calling read() to skip a byte
  public void testMark() throws Exception {
    assertTrue(counter.markSupported());
    assertEquals(10, counter.read(new byte[10]));
    assertEquals(10, counter.getCount());
    counter.mark(5);
    counter.read();

  public void testSingleSimpleStats() {
    StatsCounter counter = new SimpleStatsCounter();
    for (int i = 0; i < 11; i++) {
      counter.recordHits(1);
    }
    for (int i = 0; i < 13; i++) {
      counter.recordLoadSuccess(i);
    }
    for (int i = 0; i < 17; i++) {
      counter.recordLoadException(i);
    }
    for (int i = 0; i < 23; i++) {
      counter.recordMisses(1);
    }

                strs ->
                    new CountsHashCodeAndEquals(
                        String.join("", strs),
                        () -> counter.hashCode++,
                        () -> counter.equals++,
                        () -> counter.compareTo++)));
    assertEquals(
        result.get(0).delegateString.hashCode(),
        result.get(result.size() - 1).delegateString.hashCode());
    return result;

  private String leave() {
    return "leave";
  }

  public final void testMutualExclusion() throws Exception {
    thread1.callAndAssertReturns(enter());
    thread2.callAndAssertBlocks(enter());
    thread1.callAndAssertReturns(leave());
    thread2.assertPriorCallReturns(enter());
  }

  public final void testTryEnter() throws Exception {
    thread1.callAndAssertReturns(true, tryEnter());

    String testString = "abcdefgh";
    final CharSource source = newCharSource(testString);
    final int[] counter = new int[1];
    CharSource reader =
        new CharSource() {
          @Override
          public Reader openStream() throws IOException {
            if (counter[0]++ != 0) {
              throw new IllegalStateException("More than one source open");
            }

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright (C) 2012 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

import static org.junit.Assert.assertThrows;

import com.google.common.collect.ImmutableSet;
import java.util.HashSet;
import java.util.Set;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public final class InvalidatableSetTest {
  Set<Integer> wrappedSet;
  Set<Integer> copyOfWrappedSet;
  InvalidatableSet<Integer> setToTest;

import static org.junit.Assert.assertThrows;

import com.google.common.collect.ImmutableSet;
import java.util.HashSet;
import java.util.Set;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public final class InvalidatableSetTest {
  Set<Integer> wrappedSet;
  Set<Integer> copyOfWrappedSet;
  InvalidatableSet<Integer> setToTest;