This page provides a quick overview over the JDBC test framework. There are more examples in the release, especially one that demonstrates how to combine the JDBC test module with the other test modules of Mockrunner.

The JDBC test framework simulates a database but it does not execute any SQL statements. You can use the Mockrunner API to specify the results the database would provide when executing different SQL statements. The framework is meant for testing the Java part of JDBC based applications.

This example class simulates a bank. It can be used to transfer an amount of money from one account to another. It uses a table with the name account. The first column is the account id, the second stores the current balance.

public class Bank
{
    private Connection connection;
    
    public void connect() throws SQLException
    {
        disconnect();
        connection = 
           DriverManager.getConnection("jdbc:mysql://localhost:3306/test");
        connection.setAutoCommit(false);
    }
    
    public void disconnect() throws SQLException
    {
        if(null != connection)
        {
            connection.close();
            connection = null;
        }        
    }
    
    public void transfer(int sourceId, int targetId, int amount) 
                         throws SQLException
    {  
        PreparedStatement preparedStatement = null;
        try
        {
            if(!isValid(sourceId, amount)) return;
            preparedStatement = 
              connection.prepareStatement("update account set " +
                                          "balance=balance+? where id=?");
            preparedStatement.setInt(1, -amount);
            preparedStatement.setInt(2, sourceId);
            preparedStatement.executeUpdate();
            preparedStatement.setInt(1, amount);
            preparedStatement.setInt(2, targetId);
            preparedStatement.executeUpdate();
            connection.commit();
        }
        catch(SQLException exc)
        {
            connection.rollback();
        }
        finally
        {
            if(null != preparedStatement) preparedStatement.close();
        }
    }
    
    private boolean isValid(int sourceId, int amount) throws SQLException
    {
        Statement statement = null;
        ResultSet result = null;
        try
        {
            statement = connection.createStatement();
            result = statement.executeQuery("select balance from account "
                                            + "where id=" + sourceId);
            if(!result.next())
            {
                connection.rollback();
                return false;
            }
            int balance = result.getInt(1);
            if(balance < amount)
            {
                connection.rollback();
                return false;
            }
            return true;
        }
        catch(SQLException exc)
        {
            connection.rollback();
            return false;
        }
        finally
        {
            if(null != result) result.close();
            if(null != statement) statement.close();
        }
    }
}
				

In the first test we simulate the case that the account id does not exist, i.e. the database returns an empty ResultSet. We have to prepare an empty ResultSet and set it as the response for the select statement. Since there's only one select in this example, we can set the corresponding ResultSet as a global one, i.e. it will be returned on every test query. Mockrunner keeps track on every executed SQL statement. When preparing or verifying results you don't have to provide the complete statement string. Usually it's enough to declare just the beginning of the statement string. In this example select balance unambiguously identifies the single select statement of the application. You can also use regular expressions in more complex examples.

public class BankTest extends BasicJDBCTestCaseAdapter
{
    private void prepareEmptyResultSet()
    {
        MockConnection connection = 
            getJDBCMockObjectFactory().getMockConnection();
        StatementResultSetHandler statementHandler = 
            connection.getStatementResultSetHandler();
        MockResultSet result = statementHandler.createResultSet();
        statementHandler.prepareGlobalResultSet(result);
    }
    
    public void testWrongId() throws SQLException
    {
        prepareEmptyResultSet();
        Bank bank = new Bank();
        bank.connect();
        bank.transfer(1, 2, 5000);
        bank.disconnect();
        verifySQLStatementExecuted("select balance");
        verifySQLStatementNotExecuted("update account");
        verifyNotCommitted();
        verifyRolledBack();
        verifyAllResultSetsClosed();
        verifyAllStatementsClosed();
        verifyConnectionClosed();
    }
}
				

In the next test we simulate a valid transaction. We prepare a ResultSet with an amount of 10000, so everything is ok and the transfer can be completed. Simple responses like in this example can be easily specified using the Java API. Large response tables can be specified in text files. Check out the release for an example.

public class BankTest extends BasicJDBCTestCaseAdapter
{
    private void prepareResultSet()
    {
        MockConnection connection = 
            getJDBCMockObjectFactory().getMockConnection();
        StatementResultSetHandler statementHandler = 
            connection.getStatementResultSetHandler();
        MockResultSet result = statementHandler.createResultSet();
        result.addRow(new Integer[] {new Integer(10000)});
        statementHandler.prepareGlobalResultSet(result);
    }
    
    public void testTransferOk() throws SQLException
    {
        prepareResultSet();
        Bank bank = new Bank();
        bank.connect();
        bank.transfer(1, 2, 5000);
        bank.disconnect();
        verifySQLStatementExecuted("select balance");
        verifySQLStatementExecuted("update account");
        verifySQLStatementParameter("update account", 0, 1, new Integer(-5000));
        verifySQLStatementParameter("update account", 0, 2, new Integer(1));
        verifySQLStatementParameter("update account", 1, 1, new Integer(5000));
        verifySQLStatementParameter("update account", 1, 2, new Integer(2));
        verifyCommitted();
        verifyNotRolledBack();
        verifyAllResultSetsClosed();
        verifyAllStatementsClosed();
        verifyConnectionClosed(); 
    }
}
				

Of course there are much more things that can be done. The JDBC test framework is a test module named JDBCTestModule and works like the other test modules in Mockrunner. It provides two adapters called BasicJDBCTestCaseAdapter and JDBCTestCaseAdapter. We used the BasicJDBCTestCaseAdapter in the above example.