How do I unit test jdbc code in java? [closed]

Answer 1

Acolyte driver can be used to mock up a JDBC connection, managing it during tests and returning data as result set (with its typesafe row list API): https://github.com/cchantep/acolyte

Note: I am the author of Acolyte.

Answer 2

We use Mockrunner. http://mockrunner.sourceforge.net/ It has mock connections and datasources built in so there is no need to implement them your selves.

Answer 3

You could use DBUnit together with a HSQLDB which can read its initial data from CSV files for example.

Answer 4

I like to use a combination of:

• DBUnit
• HSQLDB
• Unitils (specifically, the database testing and maintenance modules)

You can get pretty far with just DBUnit and HSQLDB. Unitils provides the last mile of code to manage and reset database state. It also provides a nice way of managing database schema changes and makes it easy to use specific RBDMS (Oracle, DB2, SQL Server, etc). Finally, Unitils provides some nice wrappers around DBUnit which modernizes the API and makes DBUnit much more pleasant to work with.

If you haven't checked out Unitils yet, you definitely should. Unitils is often overlooked and under-appreciated.

Answer 5

There is DBUnit. It won't allow you to test your jdbc code without a database, but it seems like you could introduce a different set of buys by emulating a database.

Answer 6

If you want to do unit tests, not an integration tests, than you can use a very basic and simple approach, using Mockito only, like this:

public class JDBCLowLevelTest {

    private TestedClass tested;
    private Connection connection;
    private static Driver driver;

    @BeforeClass
    public static void setUpClass() throws Exception {
        // (Optional) Print DriverManager logs to system out
        DriverManager.setLogWriter(new PrintWriter((System.out)));

        // (Optional) Sometimes you need to get rid of a driver (e.g JDBC-ODBC Bridge)
        Driver configuredDriver = DriverManager.getDriver("jdbc:odbc:url");

        System.out.println("De-registering the configured driver: " + configuredDriver);
        DriverManager.deregisterDriver(configuredDriver);

        // Register the mocked driver
        driver = mock(Driver.class);
        System.out.println("Registering the mock driver: " + driver);
        DriverManager.registerDriver(driver);
    }

    @AfterClass
    public static void tearDown() throws Exception {
        // Let's cleanup the global state
        System.out.println("De-registering the mock driver: " + driver);
        DriverManager.deregisterDriver(driver);
    }

    @Before
    public void setUp() throws Exception {
        // given
        tested = new TestedClass();

        connection = mock(Connection.class);

        given(driver.acceptsURL(anyString())).willReturn(true);
        given(driver.connect(anyString(), Matchers.<Properties>any()))
                .willReturn(connection);

        given(connection.prepareCall(anyString())).willReturn(statement);        
    }
}

Than you can test various scenarios, like in any other Mockito test e.g.

@Test
public void shouldHandleDoubleException() throws Exception {
    // given
    SomeData someData = new SomeData();

    given(connection.prepareCall(anyString()))
            .willThrow(new SQLException("Prepare call"));
    willThrow(new SQLException("Close exception")).given(connection).close();

    // when
    SomeResponse response = testClass.someMethod(someData);

    // then
    assertThat(response, is(SOME_ERROR));
}