use h2 database in netty function test

1. Add H2 database dependency in your project. You can add the following dependency in your pom.xml file:

  com.h2database
  h2
  1.4.200

1. Create a new H2 database instance. You can create a new in-memory H2 database instance in your test setup method. For example:

import org.h2.jdbcx.JdbcDataSource;

public class MyTest {
  private JdbcDataSource dataSource;

  @Before
  public void setUp() {
    dataSource = new JdbcDataSource();
    dataSource.setURL("jdbc:h2:mem:test");
    dataSource.setUser("sa");
    dataSource.setPassword("password");
  }

  // ... your test cases ...
}

1. Use the database in your tests. You can use the H2 database instance to execute SQL queries in your tests. For example:

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class MyTest {
  private JdbcDataSource dataSource;

  // ...

  @Test
  public void testInsertAndSelect() throws SQLException {
    // create a connection to the database
    Connection conn = dataSource.getConnection();

    // insert a new row into the table
    PreparedStatement stmt = conn.prepareStatement("INSERT INTO my_table (name, age) VALUES (?, ?)");
    stmt.setString(1, "John");
    stmt.setInt(2, 30);
    stmt.executeUpdate();

    // select the row from the table
    stmt = conn.prepareStatement("SELECT name, age FROM my_table WHERE name = ?");
    stmt.setString(1, "John");
    ResultSet rs = stmt.executeQuery();

    // assert that the row exists and has the expected values
    assertTrue(rs.next());
    assertEquals("John", rs.getString("name"));
    assertEquals(30, rs.getInt("age"));

    // close the resources
    rs.close();
    stmt.close();
    conn.close();
  }
}

Note that you may need to configure your Netty application to use the same H2 database instance as your tests. You can pass the dataSource instance to your Netty application, or you can use a configuration file or environment variables to specify the database connection details.

• To use H2 database in Netty function tests and automatically add DDL, you can use the jdbc:h2:mem:test;INIT= connection string to specify the SQL statements to be executed when the database is initialized.
• For example, in your test setup method, you can create the H2 database instance with the INIT parameter like this:

import org.h2.jdbcx.JdbcDataSource;

public class MyTest {
  private JdbcDataSource dataSource;

  @Before
  public void setUp() {
    dataSource = new JdbcDataSource();
    dataSource.setURL("jdbc:h2:mem:test;INIT=RUNSCRIPT FROM 'classpath:init.sql'");
    dataSource.setUser("sa");
    dataSource.setPassword("password");
  }

  // ... your test cases ...
}

In this example, the RUNSCRIPT FROM statement in the INIT parameter specifies that the init.sql file in the classpath should be executed when the database is initialized. The init.sql file can contain your DDL statements to create tables and indexes, for example:

CREATE TABLE my_table ( id INT PRIMARY KEY, name VARCHAR(100), age INT );

 

With this setup, when the dataSource.getConnection() method is called in your test cases, the H2 database will be initialized and the DDL statements in the init.sql file will be executed automatically.

You can then use the H2 database instance to execute SQL queries in your tests, as shown in the previous example.