Mockito之使用Answer
萧懿轩
目录
Answer的基本用法：
Subject.java
public class Subject{
public int getInt(){
return 1;
}
}测试用例
Answer answer = new Answer() {
@Override
public Object answer(InvocationOnMock invocation) throws Throwable {
String method = invocation.getMethod().getName();
if(method == "getInt"){
return 0;
}
return null;
}
};
Subject subject = mock(Subject.class);
when(subject.getInt()).thenAnswer(answer);
System.out.println(subject.getInt());输出结果：0
被测试类：DataSet.java
public class DataSet {
private List<String> mData = new ArrayList(4);
private static String TAG = "DataSet";
ExecutorService mService;
public List<String> getData(ContentResolver resolver){
Uri uri = Uri.parse("uriString");
List<String> data = new ArrayList(8);
Cursor cursor = resolver.query(uri, null, null, null, null);
if(cursor != null && cursor.getCount() > 0){
while(cursor.moveToNext()){
data.add(cursor.getString(0));
}
mData = data;
return data;
}
return null;
}
public void add(String s){
if(s.startsWith("a")){
mData.add(s);
print(TAG, "info", s);
}
}
public void print(String tag, String level, String info){
System.out.println(tag + " " + level + " : " + info);
}
public void saveData(){
StringBuilder sb = new StringBuilder(64);
for(String s : mData){
sb.append(s);
}
final String data = sb.toString();
if(data.length() > 0){
Runnable runnable = new Runnable() {
@Override
public void run() {
File file = new File("data.txt");
if(file.exists()){
if(!file.delete()){
Log.e(TAG, "delete file failed!!!");
return;
}
}
FileWriter writer = null;
try {
writer = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(writer);
bw.write(data);
print(TAG, "info", "save data successed!!!");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}finally {
if(writer != null){
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
};
execute(runnable);
}
}
public void execute(Runnable task){
if(mService == null){
mService = Executors.newSingleThreadExecutor();
}
mService.execute(task);
}
}使用场景一:模拟Cursor
测试用例
final String[] arr = new String[]{"a", "b", "c", "d"};
final int count = 8;
Answer answer = new Answer() {
int size = count;
int pos = -1;
String[] data = arr;
@Override
public Object answer(InvocationOnMock invocation) throws Throwable {
String method = invocation.getMethod().getName();
switch(method){
case "moveToNext":
return ++pos < size;
case "getCount":
return size;
case "getString":
int index = invocation.getArgument(0);
if(index == 0){
return String.valueOf(data[pos%data.length]);
}
}
return null;
}
};
Cursor cursor = mock(Cursor.class, answer);
ContentResolver contentResolver = mock(ContentResolver.class);
when(contentResolver.query(any(Uri.class), (String[])isNull(), (String)isNull(),
(String[])isNull(), (String) isNull())).thenReturn(cursor);
DataSet dataSet = new DataSet();
//invoke getData()
List result = dataSet.getData(contentResolver);
//assert
assertEquals(count, result.size());
使用场景二：获取方法传入的参数，及验证参数或对参数断言
测试用例
String mStr;
@Test
public void should_str_equalsTo_mStr_when_add_with_str_startWith_a(){
Answer answer = new Answer() {
@Override
public Object answer(InvocationOnMock invocation) throws Throwable {
int indexOfInfo = 2;
mStr = invocation.getArgument(indexOfInfo);
return null;
}
};
DataSet dataSet = new DataSet();
dataSet = spy(dataSet);
doAnswer(answer).when(dataSet).print(anyString(), anyString(), anyString());
String str = "ad";
dataSet.add(str);
//验证是否走入if分支
assertEquals(str, mStr);
}
使用场景三：获取匿名内部类，对匿名内部类进行单元测试
测试用例
@Test
public void should_call_print_with_String_contains_successed_when_saveData_with_mData_not_empty(){
Answer answer = new Answer() {
@Override
public Object answer(InvocationOnMock invocation) throws Throwable {
//因为无法与runnable同步，无法验证run方法什么时候跑完，
// 所以就使用answer获取Runnable,并调用run方法
Runnable runnable = invocation.getArgument(0);
runnable.run();
return null;
}
};
DataSet dataSet = new DataSet();
dataSet = spy(dataSet);
//string startWith "a",init DataSet#mData
String data = "abb";
dataSet.add(data);
doAnswer(answer).when(dataSet).execute(any(Runnable.class));
//invoke saveData()
dataSet.saveData();
//验证成功写完数据
verify(dataSet, times(1)).print(anyString(), anyString(), contains("successed"));
}
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