How to re-create database before each test in Spring?

Using the accepted answer in Spring-Boot 2.2.0, I was seeing JDBC syntax errors related to constraints:

Caused by: org.h2.jdbc.JdbcSQLSyntaxErrorException: Constraint "FKEFFD698EA2E75FXEERWBO8IUT" already exists; SQL statement: alter table foo add constraint FKeffd698ea2e75fxeerwbo8iut foreign key (bar) references bar [90045-200]

To fix this, I added @AutoConfigureTestDatabase to my unit test (part of spring-boot-test-autoconfigure):

import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase.Replace;
import org.springframework.test.annotation.DirtiesContext;
import org.springframework.test.annotation.DirtiesContext.ClassMode;
import org.springframework.boot.test.context.SpringBootTest;
import org.junit.runner.RunWith;
import org.springframework.test.context.junit4.SpringRunner;


@RunWith(SpringRunner.class)
@SpringBootTest
@DirtiesContext(classMode = ClassMode.BEFORE_EACH_TEST_METHOD)
@AutoConfigureTestDatabase(replace = Replace.ANY)
public class FooRepositoryTest { ... }

To create the database you have to do what the other answers say with the spring.jpa.hibernate.ddl-auto=create-drop, now if your intent is to pupulate the database on each test then spring provides a very usefull anotation

@Transactional(value=JpaConfiguration.TRANSACTION_MANAGER_NAME)
@Sql(executionPhase=ExecutionPhase.BEFORE_TEST_METHOD,scripts="classpath:/test-sql/group2.sql")
public class GroupServiceTest extends TimeoffApplicationTests {

that is from this package org.springframework.test.context.jdbc.Sql; and you can run a before test method and a after test method. To populate the database.

Regarding creating the database each time, Say you only want your Test to have the create-drop option you can configure your tests with a custom properties with this annotation

@TestPropertySource(locations="classpath:application-test.properties")
public class TimeoffApplicationTests extends AbstractTransactionalJUnit4SpringContextTests{

Hope it helps

Actually, I think you want this:

@DirtiesContext(classMode = ClassMode.BEFORE_EACH_TEST_METHOD)

http://docs.spring.io/autorepo/docs/spring-framework/4.2.6.RELEASE/javadoc-api/org/springframework/test/annotation/DirtiesContext.html

@DirtiesContext may be used as a class-level and method-level annotation within the same class. In such scenarios, the ApplicationContext will be marked as dirty after any such annotated method as well as after the entire class. If the DirtiesContext.ClassMode is set to AFTER_EACH_TEST_METHOD, the context will be marked dirty after each test method in the class.

You put it on your Test class.

If you are looking for an alternative for the @DirtiesContext, this code below will help you. I used some code from this answer.

First, setup the H2 database on the application.yml file on your test resources folder:

spring: 
  datasource:
    platform: h2
    url: jdbc:h2:mem:test
    driver-class-name: org.h2.Driver
    username: sa
    password:

After that, create a class called ResetDatabaseTestExecutionListener:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.TestContext;
import org.springframework.test.context.support.AbstractTestExecutionListener;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashSet;
import java.util.Set;

public class ResetDatabaseTestExecutionListener extends AbstractTestExecutionListener {

    @Autowired
    private DataSource dataSource;

    public final int getOrder() {
        return 2001;
    }

    private boolean alreadyCleared = false;

    @Override
    public void beforeTestClass(TestContext testContext) {
        testContext.getApplicationContext()
                .getAutowireCapableBeanFactory()
                .autowireBean(this);
    }

    @Override
    public void prepareTestInstance(TestContext testContext) throws Exception {

        if (!alreadyCleared) {
            cleanupDatabase();
            alreadyCleared = true;
        }
    }

    @Override
    public void afterTestClass(TestContext testContext) throws Exception {
        cleanupDatabase();
    }

    private void cleanupDatabase() throws SQLException {
        Connection c = dataSource.getConnection();
        Statement s = c.createStatement();
   
        // Disable FK
        s.execute("SET REFERENTIAL_INTEGRITY FALSE");

        // Find all tables and truncate them
        Set<String> tables = new HashSet<>();
        ResultSet rs = s.executeQuery("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES  where TABLE_SCHEMA='PUBLIC'");
        while (rs.next()) {
            tables.add(rs.getString(1));
        }
        rs.close();
        for (String table : tables) {
            s.executeUpdate("TRUNCATE TABLE " + table);
        }

        // Idem for sequences
        Set<String> sequences = new HashSet<>();
        rs = s.executeQuery("SELECT SEQUENCE_NAME FROM INFORMATION_SCHEMA.SEQUENCES WHERE SEQUENCE_SCHEMA='PUBLIC'");
        while (rs.next()) {
            sequences.add(rs.getString(1));
        }
        rs.close();
        for (String seq : sequences) {
            s.executeUpdate("ALTER SEQUENCE " + seq + " RESTART WITH 1");
        }

        // Enable FK
        s.execute("SET REFERENTIAL_INTEGRITY TRUE");
        s.close();
        c.close();
    }
}

The code above will reset the database (truncate tables, reset sequences, etc) and is prepared to work with H2 database. If you are using another memory database (like HsqlDB) you need to make the necessary changes on the SQLs queries to accomplish the same thing.

After that, go to your test class and add the @TestExecutionListeners annotation, like:

@TestExecutionListeners(mergeMode =
        TestExecutionListeners.MergeMode.MERGE_WITH_DEFAULTS,
        listeners = {ResetDatabaseTestExecutionListener.class}
)
@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class CreateOrderIT {

This should work.

If you not see any performance difference between this approach and @DirtiesContext, probably you are using @MockBean in your tests, what marks the Spring context as dirty and automatically reload the entire context.