Powermock.whenNew和Mockito.mockConstruction的主要区别在于，Mokito在构造函数调用时，每次示例化新对象时都会创建一个新的mock，但是Powermock.whenNew可以被配置为在构造多个对象时总是返回一个mock。
根据documentation：
表示所表示类型的任何对象构造的模拟。在模拟构造的范围内，调用任何侦听器都将生成一个模拟，该模拟将在生成此范围时按指定进行准备。还可以通过此示例接收该模拟。
您可以使用MockedConstruction<T>.constructed()来获取上下文中所有生成的mock。它们可用于验证。
检查行为的测试示例：

public class A {
    private final String test;

    public A(String test) {
        this.test = test;
    }

    public String check() {
        return "checked " + this.test;
    }
}

public class TestService {
    public String purchaseProduct(String param) {
        A a = new A(param);
        return a.check();
    }
}

import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.MockedConstruction;
import org.mockito.Mockito;

import static org.mockito.Mockito.*;

public class ConstructorMockTest {
    private MockedConstruction<A> mockAController;

    @BeforeEach
    public void beginTest() {
        //create mock controller for all constructors of the given class
        mockAController = Mockito.mockConstruction(A.class,
                (mock, context) -> {
                    //implement initializer for mock. Set return value for object A mock methods
                    //this initializer will be called each time during mock creation 
                    when(mock.check()).thenReturn(" Constructor Mock A ");
                });
    }

    @Test
    public void test() {
        //each instantiation of class A will return new mock, which initialized by initializer from beginTest method
        //new mock will be stored to mockAController.constructed() collection of mocks
        A aObject = new A("test");
        //ensure that method check() returns mocked value
        Assertions.assertEquals(aObject.check(), " Constructor Mock A ");
        //get just created mock for class A from controller. It will be first element of mockAController.constructed() collection
        A aMock = mockAController.constructed().get(0);
        //ensure that we get correct mock from mock controller, that it is equal from new created object
        Assertions.assertEquals(aMock, aObject);
        //verify that check method was executed on Mock
        verify(aMock, times(1)).check();

        //create new A object, new mock created and stored to mockAController.constructed()
        A aObject2 = new A("test");
        //ensure that method check() returns mocked value
        Assertions.assertEquals(aObject2.check(), " Constructor Mock A ");
        //get just created mock for class A from controller, it will be second object from constructed collection
        A aMock2 = mockAController.constructed().get(1);
        //ensure that we get correct mock from mock controller, that it is equal from just created A object
        Assertions.assertEquals(aObject2, aMock2);
        //verify that check method was executed on Mock
        verify(aMock2, times(1)).check();

        //Example of testing service which creates A object
        TestService service = new TestService();
        String serviceResult = service.purchaseProduct("test");
        //ensure that service returned value  from A mock
        Assertions.assertEquals(serviceResult, " Constructor Mock A ");
        //get just created mock for class A from controller, it will be third object from constructed collection
        A aMock3 = mockAController.constructed().get(2);
        //verify that check method was executed on Mock
        verify(aMock3, times(1)).check();
    }

    @AfterEach
    public void endTest() {
        mockAController.close();
    }
}