Add integration tests for DDL migration scripts

[fmbenhassine]

To avoid issues like #4260 and #4271, we need to create integration tests to validate migration scripts. For PostgreSQL, it could be something like this:

/*
 * Copyright 2020-2023 the original author or 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
 *
 *      https://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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.batch.core.test.repository;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.postgresql.ds.PGSimpleDataSource;
import org.testcontainers.containers.PostgreSQLContainer;
import org.testcontainers.junit.jupiter.Container;
import org.testcontainers.junit.jupiter.Testcontainers;
import org.testcontainers.utility.DockerImageName;

import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;

/**
 * @author Mahmoud Ben Hassine
 */
@Testcontainers
class PostgreSQLMigrationScriptIntegrationTests {

	@Container
	public static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>(DockerImageName.parse("postgres:13.3"));

	@Test
	void migrationScriptShouldBeValid() {
		PGSimpleDataSource datasource = new PGSimpleDataSource();
		datasource.setURL(postgres.getJdbcUrl());
		datasource.setUser(postgres.getUsername());
		datasource.setPassword(postgres.getPassword());

		ResourceDatabasePopulator databasePopulator = new ResourceDatabasePopulator();
		databasePopulator.addScript(new ClassPathResource("/org/springframework/batch/core/schema-postgresql-4.sql"));
		databasePopulator.addScript(new ClassPathResource("/org/springframework/batch/core/migration/5.0/migration-postgresql.sql"));

		Assertions.assertDoesNotThrow(() -> databasePopulator.execute(datasource));
	}


}

For embedded databases, it could be something like this:

/*
 * Copyright 2020-2023 the original author or 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
 *
 *      https://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,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.batch.core.repository;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabase;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
import org.springframework.jdbc.datasource.init.ResourceDatabasePopulator;

/**
 * @author Mahmoud Ben Hassine
 */
class H2MigrationScriptIntegrationTests {

	@Test
	void migrationScriptShouldBeValid() {
		EmbeddedDatabase datasource = new EmbeddedDatabaseBuilder()
				.setType(EmbeddedDatabaseType.H2)
				.addScript("/org/springframework/batch/core/schema-h2-v4.sql")
				.build();

		ResourceDatabasePopulator databasePopulator = new ResourceDatabasePopulator();
		databasePopulator.addScript(new ClassPathResource("/org/springframework/batch/core/migration/5.0/migration-h2.sql"));

		Assertions.assertDoesNotThrow(() -> databasePopulator.execute(datasource));
	}


}

NB: Those tests should not be part of the CI/CD build. They can be used on demand to validate a migration script when needed.