官方文档
第一行代码，静态导入
import static org.mockito.Mockito.*;
测试桩 (Stub)
常用的当在调用外部接口的时候可以使用测试桩返回固定的一些值
//You can mock concrete classes, not only interfaces
// 你可以mock具体的类型,不仅只是接口
LinkedList mockedList = mock(LinkedList.class);
//stubbing 测试桩
when(mockedList.get(0)).thenReturn("first");
when(mockedList.get(1)).thenThrow(new RuntimeException());
//following prints "first" 输出“first”
System.out.println(mockedList.get(0));
//following throws runtime exception 抛出异常
System.out.println(mockedList.get(1));
//following prints "null" because get(999) was not stubbed
// 因为get(999) 没有打桩，因此输出null
System.out.println(mockedList.get(999));
mock 异常抛出
无返回值
doThrow(new RuntimeException()).when(mockedList).clear();
有返回值的
when(mockedList.get(anyInt())).thenThrow(new RuntimeException());
参数匹配器 (matchers)
当参数可能不确定的时候 anyInt() 来匹配
// 使用内置的anyInt()参数匹配器
when(mockedList.get(anyInt())).thenReturn("element");
为连续的调用做测试桩 (stub)
List mockedList = mock(List.class);
when(mockedList.get(anyInt()))
.thenThrow(new RuntimeException())
.thenReturn("foo");
// First call: throws runtime exception:
// 第一次调用 : 抛出运行时异常
try {
mockedList.get(2);
} catch (Exception e) {
System.out.println("有异常");
}
// Second call: prints "foo"
// 第二次调用 : 输出"foo"
System.out.println(mockedList.get(3));
// Any consecutive call: prints "foo" as well (last stubbing wins).
// 后续调用 : 也是输出"foo"
System.out.println(mockedList.get(4));
简化写法
// 第一次调用时返回"one",第二次返回"two",第三次返回"three"
when(mock.someMethod("some arg"))
.thenReturn("one", "two", "three");
为回调写测试桩(有返回值)
when(mock.someMethod(anyString())).thenAnswer(new Answer() {
Object answer(InvocationOnMock invocation) {
Object[] args = invocation.getArguments();
Object mock = invocation.getMock();
return "called with arguments: " + args;
}
});
//Following prints "called with arguments: foo"
// 输出 : "called with arguments: foo"
System.out.println(mock.someMethod("foo"));
List mockedList = mock(List.class);
mockedList.add("haha");
when(mockedList.get(anyInt())).thenAnswer(
(invocation) -> {
// 获取所有参数
Object[] args = invocation.getArguments();
// 获取第一个参数
Object firstArgs = invocation.getArgument(0);
return "called with arguments: " + firstArgs;
});
// 最后答应出 回调函数中的东西
System.out.println(mockedList.get(2));
回调测试桩
这样写可能更好，注意这时候when监控的是 mockedList
doAnswer(x->{
System.out.println("clear");
return null;
}).when(mockedList).clear();
mockedList.clear();
verify 验证你的程序
verify(mockedList, atLeastOnce()).add("three times");
比如 至少被执行两次，如果只 add 一次就会报错
List mockedList = mock(List.class);
mockedList.add("one");
mockedList.add("one");
verify(mockedList,atLeast(2)).add("one");
