当我尝试使用这个mock时，我得到了错误Checked exception is invalid for this method：

InitialContext mockContext;
mockContext = mock(InitialContext.class);
when((DataSource) mockContext.lookup("java:comp/env/jdbc/foo")).thenThrow(new ConnectionFactoryException("test")); // <-- Fails on this line
@Test
public void shouldThrowExceptionIfDataSourceDoesNotExist() throws ConnectionFactoryException {
    assertThatExceptionOfType(ConnectionFactoryException.class)
        .isThrownBy(() -> { new DataSourceFactory(mockContext).getDataSource("foo"); })
        .withMessage("Unable to find jdbc/foo");
}

我试着考类：

public class DataSourceFactory {
    // Dependencies to be injected
    private InitialContext context;
    public DataSourceFactory(InitialContext context) throws ConnectionFactoryException {
        if(context == null) {
            throw new ConnectionFactoryException("context can't be null");
        }
        this.context = context;
    }
    public DataSource getDataSource(String dataSourceName) throws ConnectionFactoryException {
        if(dataSourceName == null) {
            throw new ConnectionFactoryException("dataSourceName can't be null");
        }
        // Ensure we have the correct syntax for the datasource name
        if(!dataSourceName.startsWith("jdbc/")) {
            dataSourceName = "jdbc/" + dataSourceName;
        }
        try {
            System.out.println("java:comp/env/" + dataSourceName);
            DataSource dataSource = (DataSource) context.lookup("java:comp/env/" + dataSourceName);
            return dataSource;
        } catch (NamingException e) {
            throw new ConnectionFactoryException("Unable to find " + dataSourceName, e);
        }
    }
}

我知道我已经读到不应该模拟我不拥有的对象，但是我不知道如何在不模拟InitialContext的情况下测试getDataSource()方法。