int oldValue = multiset.remove(key, delta);
              deltas[keyIndex] -= Math.min(delta, oldValue);
              break;
            }
          case REMOVE_EXACTLY:
            {
              int delta = random.nextInt(5); // [0, 4]
              if (multiset.removeExactly(key, delta)) {
                deltas[keyIndex] -= delta;
              }
              break;

              int oldValue = multiset.remove(key, delta);
              deltas[keyIndex] -= Math.min(delta, oldValue);
              break;
            }
          case REMOVE_EXACTLY:
            {
              int delta = random.nextInt(5); // [0, 4]
              if (multiset.removeExactly(key, delta)) {
                deltas[keyIndex] -= delta;
              }
              break;

      <plugin>
        <groupId>org.apache.maven.its.plugins</groupId>
        <artifactId>maven-it-plugin-a</artifactId>
        <version>1.0-SNAPSHOT</version>
        <dependencies>
          <!-- NOTE: That's exactly the same dependency as for the other plugin. -->
          <dependency>
            <groupId>org.apache.maven.its.mng3838</groupId>
            <artifactId>dep</artifactId>
            <version>123</version>

   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */
  @SuppressWarnings("unchecked")
  public static <T> Collector<T, ?, Optional<T>> toOptional() {

You could want to set up a different database for testing, rollback the data after the tests, pre-fill it with some testing data, etc.

The main idea is exactly the same you saw in that previous chapter.

## Add tests for the SQL app

Let's update the example from [SQL (Relational) Databases](../tutorial/sql-databases.md){.internal-link target=_blank} to use a testing database.

 *
 * @author Louis Wasserman
 */
public class OutsideEventBusTest extends TestCase {

  /*
   * If you do this test from common.eventbus.EventBusTest, it doesn't actually test the behavior.
   * That is, even if exactly the same method works from inside the common.eventbus package tests,
   * it can fail here.
   */
  public void testAnonymous() {
    final AtomicReference<String> holder = new AtomicReference<>();

   */
  protected final void expectContents(E... elements) {
    expectContents(Arrays.asList(elements));
  }

  /**
   * Asserts that the collection under test contains exactly the given elements, respecting
   * cardinality but not order. Subclasses may override this method to provide stronger assertions,
   * e.g., to check ordering in lists, but realize that <strong>unless a test extends {@link

package lifecycle

import (
	"encoding/xml"
	"io"

	"github.com/minio/minio-go/v7/pkg/tags"
)

var errInvalidFilter = Errorf("Filter must have exactly one of Prefix, Tag, or And specified")

// Filter - a filter for a lifecycle configuration Rule.
type Filter struct {
	XMLName xml.Name `xml:"Filter"`
	set     bool

	Prefix Prefix

  // +optional
  optional string failurePolicy = 4;

  // matchPolicy defines how the "rules" list is used to match incoming requests.
  // Allowed values are "Exact" or "Equivalent".
  //
  // - Exact: match a request only if it exactly matches a specified rule.
  // For example, if deployments can be modified via apps/v1, apps/v1beta1, and extensions/v1beta1,

   */
  protected final void expectContents(E... elements) {
    expectContents(Arrays.asList(elements));
  }

  /**
   * Asserts that the collection under test contains exactly the given elements, respecting
   * cardinality but not order. Subclasses may override this method to provide stronger assertions,
   * e.g., to check ordering in lists, but realize that <strong>unless a test extends {@link