我想测试一个静态方法（例如HobbyUtil.java:shareReadContext(int lineNumber)），该方法将要求Singleton类（例如Shelf.java）获取对象（例如Book）以进行进一步检索值（例如上下文行）返回的对象。
但是，在模拟案例执行期间，该Singleton类（即Shelf.java）的ctor会触发链中的其他几个Singleton类（例如libraryA.java）；并且其中之一会触发java.lang.ExceptionInInitializerError。
我认为模拟/监视那些不相关的Singleton类超出了Mock Test的精神，因为它们与我的测试范围无关。
因此，我决定取消此Singleton类（即Shelf.java）的私有ctor，只让该类中的getter方法（即getBook()）返回具有我喜欢的行为的模拟对象，完全符合我的测试用例。
我遇到的问题是我点击此链接成功抑制了 Shelf.java 的错误： suppress a singleton constructor in java with powermock
但是我无法弄清楚让这个getter方法返回我想要的东西（即返回一个模拟对象）的方法。
我正在使用的 PowerMockito ， hamcrest 和 JUnit 的版本在此处列出以供参考：
<dependency><groupId>org.powermock</groupId><artifactId>powermock-module-junit4</artifactId><version>1.7.0</version><scope>test</scope></dependency>
<dependency><groupId>org.powermock</groupId><artifactId>powermock-api-mockit02</artifactId><version>1.7.0</version><scope>test</scope></dependency>
<dependency><groupId>org.hamcrest</groupId><artifactId>hamcrest-all</artifactId><version>1.3</version><scope>test</scope></dependency>
<dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope></dependency>
我还用下面的示例类复制了该案例，以显示遇到的问题（HobbyUtilTest.java是我的测试案例的类）：
假设应用程序中有5个Java类：
public interface Book {
public String getcontext(int lineNumber);
}
public class Shelf {
private static final Shelf shelf = new Shelf();
private String BOOK_NAME = "HarryPotter";
private Book book = null;
private Shelf() {
book = libraryA.getInstance().getBook(BOOK_NAME);
// many relatively complicated logics are here in actual class ...
// I want to suppress this ctor
}
public static Shelf getInstance() {
return shelf;
}
public Book getBook() {
return book; // I want to return my mocked object while calling this method in test case
}
}
public class HobbyUtil {
public static String shareReadContext(int lineNumber){
String context = "";
Book book = Shelf.getInstance().getBook();
for (int i = 0 ; i < lineNumber; i++) {
context += book.getcontext(i);
}
return context;
}
private HobbyUtil() {}
}
public class libraryA {
private static final libraryA library = new libraryA();
private Book book;
private libraryA() {
throw new java.lang.ExceptionInInitializerError();
}
public static libraryA getInstance() {
return library;
}
public Book getBook(String bookName) {
return book;
}
}
public class BookImpl implements Book{
private String bookName = null;
BookImpl(String bookName){
this.bookName = bookName;
}
@Override
public String getcontext(int lineNumber) {
return lineNumber + ": Context";
}
}
然后我将使用shareReadContext(int lineNumber)在HobbyUtil.java中测试静态方法HobbyUtilTest.java
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.powermock.api.mockito.PowerMockito.when;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
@RunWith(PowerMockRunner.class)
@PrepareForTest(value = { Shelf.class })
public class HobbyUtilTest {
@Test
public void testShareReadContext() throws Exception {
Book mockBook = PowerMockito.mock(Book.class);
when(mockBook.getcontext(anyInt())).thenReturn("context for test");
PowerMockito.suppress(PowerMockito.constructor(Shelf.class));
//PowerMockito.spy(Shelf.class);
//when(Shelf.getInstance().getBook()).thenReturn(mockBook); // does not work
//PowerMockito.doReturn(mockBook).when(Shelf.getInstance().getBook()); // does not work
//PowerMockito.when(Shelf.class,"getBook").thenReturn(mockBook); // does not work
//TODO any approach for it?
String context = HobbyUtil.shareReadContext(1);
assertThat(context,is("context for test"));
}
}
有人可以帮助建议我如何让Book book = Shelf.getInstance().getBook();中的行HobbyUtil.java返回我的模拟对象（即mockBook）吗？