@CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNull_supported() {
    E[] array = createArrayWithNullElement();
    collection = getSubjectGenerator().create(array);
    expectContents(array);
  }

  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNull_unsupported() {

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

/*
 * Source:
 * http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jsr166e/LongAdder.java?revision=1.17
 */

package com.google.common.cache;

import com.google.common.annotations.GwtCompatible;

  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testClear_unsupported() {
    assertThrows(UnsupportedOperationException.class, () -> collection.clear());
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testClear_unsupportedByEmptyCollection() {
    try {
      collection.clear();

   * @return the count of the element before the operation; possibly zero
   * @throws IllegalArgumentException if {@code count} is negative
   * @throws NullPointerException if {@code element} is null and this implementation does not permit
   *     null elements. Note that if {@code count} is zero, the implementor may optionally return
   *     zero instead.
   */
  @CanIgnoreReturnValue

      if (values.size() >= 3) {
        b = values.get(1);
        c = values.get(2);
      }
    }
  }

  @CollectionSize.Require(ZERO)
  public void testEmptySetFirst() {
    assertThrows(NoSuchElementException.class, () -> sortedSet.first());
  }

  @CollectionSize.Require(ZERO)
  public void testEmptySetLast() {
    assertThrows(NoSuchElementException.class, () -> sortedSet.last());
  }

  @CollectionSize.Require(ONE)

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nonNullWhenNullContained() {
    initCollectionWithNullElement();
    assertFalse("contains(notPresent) should return false", collection.contains(e3()));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initCollectionWithNullElement();

  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nonNullWhenNullContained() {
    initMapWithNullValue();
    assertFalse("containsValue(notPresent) should return false", getMap().containsValue(v3()));
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initMapWithNullValue();

import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.AbstractCollectionTester;
import com.google.common.collect.testing.features.CollectionFeature;

#### Um ataque "profissional"

Claro, os invasores não tentariam tudo isso de forma manual, eles escreveriam um programa para fazer isso, possivelmente com milhares ou milhões de testes por segundo. E obteriam apenas uma letra a mais por vez.

* `allow_origins` - Uma lista de origens que devem ter permissão para fazer requisições de origem cruzada. Por exemplo, `['https://example.org', 'https://www.example.org']`. Você pode usar `['*']` para permitir qualquer origem.
* `allow_origin_regex` - Uma string regex para corresponder às origens que devem ter permissão para fazer requisições de origem cruzada. Por exemplo, `'https://.*\.example\.org'`.