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());
}
}
其他回答
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);
}
}
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());
}
}
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);
在Mockito之上使用PowerMockito。
示例代码:
@RunWith(PowerMockRunner.class)
@PrepareForTest(DriverManager.class)
public class Mocker {
@Test
public void shouldVerifyParameters() throws Exception {
//given
PowerMockito.mockStatic(DriverManager.class);
BDDMockito.given(DriverManager.getConnection(...)).willReturn(...);
//when
sut.execute(); // System Under Test (sut)
//then
PowerMockito.verifyStatic();
DriverManager.getConnection(...);
}
更多信息:
为什么Mockito不模拟静态方法?
对于模仿静态函数，我能够这样做:
在helper类/对象中创建一个包装器函数。(使用名称变体可能有助于保持内容的分离和可维护。) 在代码中使用此包装器。(是的，代码的实现需要考虑到测试。) 模拟包装器函数。
包装器代码片段(不是真正的功能，只是为了说明)
class myWrapperClass ...
def myWrapperFunction (...) {
return theOriginalFunction (...)
}
当然，在一个包装器类中积累多个这样的函数可能有利于代码重用。
