接下來我們將以MyDictionary類為例進(jìn)行介紹
class MyDictionary {
private Map<String, String> wordMap;
MyDictionary() {
wordMap = new HashMap<>();
}
public void add(final String word, final String meaning) {
wordMap.put(word, meaning);
}
String getMeaning(final String word) {
return wordMap.get(word);
}
}
1 Mock對象模擬異常
1.1 方法返回類型非void
如果方法的返回類型非void,那么可以使用when().thenThrow()來模擬異常
@Test(expected = NullPointerException.class)
public void whenConfigNonVoidRetunMethodToThrowEx_thenExIsThrown() {
MyDictionary dictMock = mock(MyDictionary.class);
when(dictMock.getMeaning(anyString())).thenThrow(NullPointerException.class);
dictMock.getMeaning("word");
}
1.2 方法返回類型是void
如果方法返回類型是void,則使用doThrow來模擬異常
@Test(expected = IllegalStateException.class)
public void whenConfigVoidRetunMethodToThrowEx_thenExIsThrown() {
MyDictionary dictMock = mock(MyDictionary.class);
doThrow(IllegalStateException.class)
.when(dictMock)
.add(anyString(), anyString());
dictMock.add("word", "meaning");
}
1.3 模擬異常對象
我們不僅可以在thenThrow()或者doThrow() 中模擬異常類,還可以模擬異常對象。
@Test(expected = NullPointerException.class)
public void whenConfigNonVoidRetunMethodToThrowExWithNewExObj_thenExIsThrown() {
MyDictionary dictMock = mock(MyDictionary.class);
when(dictMock.getMeaning(anyString())).thenThrow(new NullPointerException("Error occurred"));
dictMock.getMeaning("word");
}
@Test(expected = IllegalStateException.class)
public void whenConfigVoidRetunMethodToThrowExWithNewExObj_thenExIsThrown() {
MyDictionary dictMock = mock(MyDictionary.class);
doThrow(new IllegalStateException("Error occurred")).when(dictMock)
.add(anyString(), anyString());
dictMock.add("word", "meaning");
}
2 Spy對象模擬異常
Spy對象模擬異常的方式與Mock對象相同潘明,如下:
@Test(expected = NullPointerException.class)
public void givenSpy_whenConfigNonVoidRetunMethodToThrowEx_thenExIsThrown() {
MyDictionary dict = new MyDictionary();
MyDictionary spy = Mockito.spy(dict);
when(spy.getMeaning(anyString()))
.thenThrow(NullPointerException.class);
spy.getMeaning("word");
}