example: mockito

dunwu · dunwu · commit 21a99080b73e · 2018-11-30T08:57:15.000+08:00
diff --git a/codes/javalib/test/src/test/java/io/github/dunwu/javalib/mockito/MockitoTest.java b/codes/javalib/test/src/test/java/io/github/dunwu/javalib/mockito/MockitoTest.java
@@ -0,0 +1,208 @@
+package io.github.dunwu.javalib.mockito;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InOrder;
+
+import java.util.LinkedList;
+import java.util.List;
+
+import static org.mockito.Mockito.*;
+
+class MockitoTest {
+    // 模拟 LinkedList 的一个对象
+    LinkedList mockedList = mock(LinkedList.class);
+
+    @BeforeEach
+    void beforeEach() {
+        mockedList.clear();
+    }
+
+    @Test
+    void test() {
+        //using mock object - it does not throw any "unexpected interaction" exception
+        mockedList.add("one");
+        // selective, explicit, highly readable verification
+        verify(mockedList).add("one");
+    }
+
+    /**
+     * 模拟对象
+     */
+    @Test
+    void test01() {
+        // 此时调用get方法，会返回null，因为还没有对方法调用的返回值做模拟
+        System.out.println(mockedList.get(0));
+    }
+
+    /**
+     * 模拟方法调用的返回值
+     */
+    @Test
+    void test02() {
+        // 模拟获取第一个元素时，返回字符串first。给特定的方法调用返回固定值在官方说法中称为stub。
+        when(mockedList.get(0)).thenReturn("first");
+        // 此时打印输出first
+        System.out.println(mockedList.get(0));
+    }
+
+    /**
+     * 模拟方法调用抛出异常
+     */
+    @Test
+    void test03() {
+        // 模拟获取第二个元素时，抛出RuntimeException
+        when(mockedList.get(1)).thenThrow(new RuntimeException());
+        // 此时将会抛出RuntimeException
+        System.out.println(mockedList.get(1));
+    }
+
+    /**
+     * 模拟方法调用抛出异常2
+     */
+    @Test
+    void test04() {
+        doThrow(new RuntimeException("clear exception")).when(mockedList).clear();
+        mockedList.clear();
+    }
+
+    /**
+     * 模拟调用方法时的参数匹配
+     */
+    @Test
+    void test05() {
+        // anyInt()匹配任何int参数，这意味着参数为任意值，其返回值均是element
+        when(mockedList.get(anyInt())).thenReturn("element");
+        // 此时打印是element
+        System.out.println(mockedList.get(999));
+    }
+
+    /**
+     * 模拟方法调用次数
+     */
+    @Test
+    void test06() {
+        // 调用add一次
+        mockedList.add("once");
+        // 下面两个写法验证效果一样，均验证add方法是否被调用了一次
+        verify(mockedList).add("once");
+        verify(mockedList, times(1)).add("once");
+    }
+
+    /**
+     * 校验行为
+     */
+    @Test
+    void test07() {
+        // using mock object
+        mockedList.add("one");
+        mockedList.clear();
+        //verification
+        verify(mockedList).add("one");
+        verify(mockedList).clear();
+    }
+
+    /**
+     * 模拟方法调用(Stubbing)
+     */
+    @Test
+    void test08() {
+        //stubbing
+        when(mockedList.get(0)).thenReturn("first");
+        when(mockedList.get(1)).thenThrow(new RuntimeException());
+        //following prints "first"
+        System.out.println(mockedList.get(0));
+        //following throws runtime exception
+        System.out.println(mockedList.get(1));
+        //following prints "null" because get(999) was not stubbed
+        System.out.println(mockedList.get(999));
+
+        verify(mockedList).get(0);
+    }
+
+    /**
+     * 校验方法调用次数
+     */
+    @Test
+    void test09() {
+        //using mock
+        mockedList.add("once");
+
+        mockedList.add("twice");
+        mockedList.add("twice");
+
+        mockedList.add("three times");
+        mockedList.add("three times");
+        mockedList.add("three times");
+        //following two verifications work exactly the same - times(1) is used by default
+        verify(mockedList).add("once");
+        verify(mockedList, times(1)).add("once");
+        //exact number of invocations verification
+        verify(mockedList, times(2)).add("twice");
+        verify(mockedList, times(3)).add("three times");
+        //verification using never(). never() is an alias to times(0)
+        verify(mockedList, never()).add("never happened");
+        //verification using atLeast()/atMost()
+        verify(mockedList, atLeastOnce()).add("three times");
+        verify(mockedList, atLeast(2)).add("five times");
+        verify(mockedList, atMost(5)).add("three times");
+    }
+
+    /**
+     * 校验方法调用顺序
+     */
+    @Test
+    void test10() {
+        // A. Single mock whose methods must be invoked in a particular order
+        List singleMock = mock(List.class);
+        //using a single mock
+        singleMock.add("was added first");
+        singleMock.add("was added second");
+        //create an inOrder verifier for a single mock
+        InOrder inOrder = inOrder(singleMock);
+        //following will make sure that add is first called with "was added first, then with "was added second"
+        inOrder.verify(singleMock).add("was added first");
+        inOrder.verify(singleMock).add("was added second");
+
+        // B. Multiple mocks that must be used in a particular order
+        List firstMock = mock(List.class);
+        List secondMock = mock(List.class);
+        //using mocks
+        firstMock.add("was called first");
+        secondMock.add("was called second");
+        //create inOrder object passing any mocks that need to be verified in order
+        inOrder = inOrder(firstMock, secondMock);
+        //following will make sure that firstMock was called before secondMock
+        inOrder.verify(firstMock).add("was called first");
+        inOrder.verify(secondMock).add("was called second");
+        // Oh, and A + B can be mixed together at will
+    }
+
+    /**
+     * 校验方法是否从未调用
+     */
+    @Test
+    void test11() {
+        List mockOne = mock(List.class);
+        List mockTwo = mock(List.class);
+        List mockThree = mock(List.class);
+        //using mocks - only mockOne is interacted
+        mockOne.add("one");
+        //ordinary verification
+        verify(mockOne).add("one");
+        //verify that method was never called on a mock
+        verify(mockOne, never()).add("two");
+        //verify that other mocks were not interacted
+        verifyZeroInteractions(mockTwo, mockThree);
+    }
+
+    /**
+     * 重置Mock
+     */
+    void test12() {
+        List mock = mock(List.class);
+        when(mock.size()).thenReturn(10);
+        mock.add(1);
+        reset(mock);
+    }
+}
