Hibernate: unknown entity

Хочу научиться использовать Hibernate и разбираю такой пример из книги:

package models;
import javax.persistence.*;
@Entity
public class Message {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    Long id;
    @Column(nullable = false)
    String text;
    public Message() {
    }
    public Message(String text) {
        setText(text);
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getText() {
        return text;
    }
    public void setText(String text) {
        this.text = text;
    }
    @Override
    public String toString() {
        return "Message{" +
                "id = " + getId() +
                ", text = '" + getText() + '\'' +
                "}";
    }
}

TestNG:

package models;
import javax.persistence.*;
@Entity
public class Message {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    Long id;
    @Column(nullable = false)
    String text;
    public Message() {
    }
    public Message(String text) {
        setText(text);
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getText() {
        return text;
    }
    public void setText(String text) {
        this.text = text;
    }
    @Override
    public String toString() {
        return "Message{" +
                "id = " + getId() +
                ", text = '" + getText() + '\'' +
                "}";
    }
}

hibernate.cfg.xml:

<?xml version="1.0"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="connection.driver_class">
            org.hsqldb.jdbc.JDBCDriver
        </property>
        <property name="connection.url">
            jdbc:hsqldb:db2;shutdown=true
        </property>
        <property name="connection.username">sa</property>
        <property name="connection.password"/>
        <property name="dialect">org.hibernate.dialect.HSQLDialect</property>
        <property name="show_sql">true</property>
        <property name="hbm2ddl.auto">create-drop</property>
        <mapping class="models.Message"/>
    </session-factory>
</hibernate-configuration>

При запуске теста получаю ошибку:

авг 10, 2018 1:37:42 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.3.4.Final}
авг 10, 2018 1:37:42 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
авг 10, 2018 1:37:42 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.0.4.Final}
авг 10, 2018 1:37:42 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
авг 10, 2018 1:37:42 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [org.hsqldb.jdbc.JDBCDriver] at URL [jdbc:hsqldb:db2;shutdown=true]
авг 10, 2018 1:37:42 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {user=sa, password=****}
авг 10, 2018 1:37:42 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
авг 10, 2018 1:37:42 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 20 (min=1)
java.lang.IllegalArgumentException: Unknown entity: models.Message
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:804)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:785)
    at models.PersistenceTest.saveMessage(PersistenceTest.java:31)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:583)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:719)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:989)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109)
    at org.testng.TestRunner.privateRun(TestRunner.java:648)
    at org.testng.TestRunner.run(TestRunner.java:505)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:455)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:450)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:415)
    at org.testng.SuiteRunner.run(SuiteRunner.java:364)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:84)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1208)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1137)
    at org.testng.TestNG.runSuites(TestNG.java:1049)
    at org.testng.TestNG.run(TestNG.java:1017)
    at org.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:72)
    at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:123)

Клас сущности определен в пакете models и размечен. что я делаю не так?