java 具有泛型和返回类型扩展的模拟方法
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mock method with generic and extends in return type
提问by piotrek
Is it possible to mock (with mockito) method with signature Set<? extends Car> getCars()without supress warnings? i tried:
是否可以在Set<? extends Car> getCars()没有抑制警告的情况下模拟（使用 mockito）带有签名的方法？我试过：
XXX cars = xxx;
when(owner.getCars()).thenReturn(cars);
but no matter how i declare carsi alway get a compilation error.
e.g when i declare like this
但无论我如何声明，cars我总是会遇到编译错误。例如，当我这样声明时
Set<? extends Car> cars = xxx
i get the standard generic/mockito compilation error
我得到标准的泛型/mockito 编译错误
The method thenReturn(Set<capture#1-of ? extends Car>) in the type OngoingStubbing<Set<capture#1-of ? extends Car>> is not applicable for the arguments (Set<capture#2-of ? extends Car>)
回答by Tom Tresansky
Use the doReturn-when alternate stubbing syntax.
使用 doReturn-when 替代存根语法。
System under test:
被测系统：
public class MyClass {
Set<? extends Number> getSet() {
return new HashSet<Integer>();
}
}
and the test case:
和测试用例：
import static org.mockito.Mockito.*;
import java.util.HashSet;
import java.util.Set;
import org.junit.Test;
public class TestMyClass {
@Test
public void testGetSet() {
final MyClass mockInstance = mock(MyClass.class);
final Set<Integer> resultSet = new HashSet<Integer>();
resultSet.add(1);
resultSet.add(2);
resultSet.add(3);
doReturn(resultSet).when(mockInstance).getSet();
System.out.println(mockInstance.getSet());
}
}
No errors or warning suppression needed
不需要错误或警告抑制
