我写了一个工厂来产生java.sql.Connection对象:

public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory {

    @Override public Connection getConnection() {
        try {
            return DriverManager.getConnection(...);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

我想验证传递给DriverManager的参数。getConnection,但我不知道如何模拟静态方法。我的测试用例使用JUnit 4和Mockito。是否有一个好的方法来模拟/验证这个特定的用例?


当前回答

我还编写了Mockito和AspectJ的组合:https://github.com/iirekm/varia/tree/develop/ajmock

你的例子是:

when(() -> DriverManager.getConnection(...)).thenReturn(...);

其他回答

使用JMockit框架。这对我很管用。您不必为模拟dbconnection . getconnection()方法编写语句。只要下面的代码就足够了。

下面的@Mock是mockit。模拟方案

Connection jdbcConnection = Mockito.mock(Connection.class);

MockUp<DBConnection> mockUp = new MockUp<DBConnection>() {

            DBConnection singleton = new DBConnection();

            @Mock
            public DBConnection getInstance() { 
                return singleton;
            }

            @Mock
            public Connection getConnection() {
                return jdbcConnection;
            }
         };

由于该方法是静态的,它已经具备了使用它所需的一切,因此它违背了模拟的目的。 模仿静态方法被认为是一种糟糕的实践。

如果您尝试这样做,这意味着您想要执行测试的方式有问题。

当然,您可以使用PowerMockito或任何其他能够做到这一点的框架,但请重新考虑您的方法。

例如:尝试模拟/提供对象,而静态方法使用这些对象。

我也遇到过类似的问题。根据PowerMock的mockStatic文档,接受的答案对我不起作用,直到我做出了更改:@PrepareForTest(classthatcontainsstaticmethod .class)。

我不需要使用BDDMockito。

我的类:

public class SmokeRouteBuilder {
    public static String smokeMessageId() {
        try {
            return InetAddress.getLocalHost().getHostAddress();
        } catch (UnknownHostException e) {
            log.error("Exception occurred while fetching localhost address", e);
            return UUID.randomUUID().toString();
        }
    }
}

我的测试类:

@RunWith(PowerMockRunner.class)
@PrepareForTest(SmokeRouteBuilder.class)
public class SmokeRouteBuilderTest {
    @Test
    public void testSmokeMessageId_exception() throws UnknownHostException {
        UUID id = UUID.randomUUID();

        mockStatic(InetAddress.class);
        mockStatic(UUID.class);
        when(InetAddress.getLocalHost()).thenThrow(UnknownHostException.class);
        when(UUID.randomUUID()).thenReturn(id);

        assertEquals(id.toString(), SmokeRouteBuilder.smokeMessageId());
    }
}

你可以做一点重构:

public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory {

    @Override public Connection getConnection() {
        try {
            return _getConnection(...some params...);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    //method to forward parameters, enabling mocking, extension, etc
    Connection _getConnection(...some params...) throws SQLException {
        return DriverManager.getConnection(...some params...);
    }
}

然后你可以扩展你的MySQLDatabaseConnectionFactory类来返回一个模拟的连接,对参数进行断言等等。

扩展类可以驻留在测试用例中,如果它位于相同的包中(我鼓励您这样做)

public class MockedConnectionFactory extends MySQLDatabaseConnectionFactory {

    Connection _getConnection(...some params...) throws SQLException {
        if (some param != something) throw new InvalidParameterException();

        //consider mocking some methods with when(yourMock.something()).thenReturn(value)
        return Mockito.mock(Connection.class);
    }
}

稍微重构一下:

public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory {
    ConnectionSupplier connectionSupplier = () -> SupplierDriverManager.getConnection();

    public void setConnSupplier(ConnectionSupplier supplier) {
        this.connectionSupplier = supplier;
    }

    @Override 
    public Connection getConnection() {
        try {
            return connectionSupplier.conn();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
    @FunctionalInterface
    interface ConnectionSupplier {
        Connection conn();
    }
}

然后你可以使用mockito:

MySQLDatabaseConnectionFactory.ConnectionSupplier connectionSupplier = mock(MySQLDatabaseConnectionFactory.ConnectionSupplier.class);
when(connectionSupplier.conn()).thenReturn(yourMockObject);
yourConnectionFactory.setConnSupplier(connectionSupplier);