想要但不是援引：Mockito PrintWriter

Question

嗨我正在一个项目和使用PrintWriter类打开和写入文件。但是，当我在为同一写测试用例它给了以下错误在线路153

Wanted but not invoked: 
    mockPrintWriter.println("ID url1 
    "); 
-> at x.y.z.verify(ProcessImageDataTest.java:153) 
Actually, there were zero interactions with this mock. 

代码：（使用龙目岛库）

ProcessImageData.java

@Setter 
@RequiredArgsConstructor 
public class ProcessImageData implements T { 
    private final File newImageDataTextFile; 

    @Override 
    public void execute() { 
     LineIterator inputFileIterator = null; 
     try { 
     File filteredImageDataTextFile = new File(filteredImageDataTextFilepath); 

      PrintWriter writer = new PrintWriter(newImageDataTextFile); 
      inputFileIterator = FileUtils.lineIterator(filteredImageDataTextFile, StandardCharsets.UTF_8.displayName()); 
      while (inputFileIterator.hasNext()) { 
        if(someCondition) 
      **Line51**   writer.println(imageDataFileLine); 
        //FileUtils.writeStringToFile(newImageDataTextFile, imageDataFileLine + NEWLINE, true); 
       } 
      }   

     } catch (Exception e) { 

     } finally { 
      LineIterator.closeQuietly(inputFileIterator); 
**LINE63**   writer.close(); 
     } 
    } 

ProcessImageDataTest.java

@RunWith(PowerMockRunner.class) 
@PrepareForTest({ ProcessImageData.class, FileUtils.class, Printwriter.class }) 
public class ProcessImageDataTest { 

private ProcessImageData processImageData; 

private static final String FILTERED_IMAGE_DATA_TEXT_FILE_PATH = "filteredFilepath"; 
private File FILTEREDFILE = new File(FILTERED_PATH); 
private static final File IMAGE__FILE = new File("imageFilePath"); 

private LineIterator lineIterator; 
@Mock 
private PrintWriter mockPrintWriter; 

@Before 
public void init() throws Exception { 
    MockitoAnnotations.initMocks(this); 

    processImageData = new ProcessImageData(Palettes_file, FILTERED_PATH, IMAGE_FILE); 

    PowerMockito.mockStatic(FileUtils.class); 
    PowerMockito.whenNew(PrintWriter.class).withArguments(IMAGE_FILE).thenReturn(mockPrintWriter); 

    PowerMockito.when(FileUtils.lineIterator(FILTERED_FILE, StandardCharsets.UTF_8.displayName())).thenReturn(lineIterator); 
    PowerMockito.when(lineIterator.hasNext()).thenReturn(true, true, false); 

} 

@Test 
public void testTaskWhenIDInDBAndStale() throws IOException { 
    PowerMockito.when(lineIterator.nextLine()).thenReturn(ID2 + SPACE + URL1, ID1 + SPACE + URL2); 

    processImageData.execute(); 

    List<String> exepctedFileContentOutput = Arrays.asList(ID2 + SPACE + URL1 + NEWLINE); 
    verify(exepctedFileContentOutput, 1, 1); 
} 


@Test 
public void testTaskWhenIDNotInDB() throws IOException { 
    PowerMockito.when(lineIterator.nextLine()).thenReturn(ID2 + SPACE + URL1, ID3 + SPACE + URL2); 

    processImageData.execute(); 

    List<String> exepctedFileContentOutput = Arrays.asList(ID3 + SPACE + URL2 + NEWLINE); 
    verify(exepctedFileContentOutput, 1, 1); 
} 

private void verify(List<String> exepctedFileContentOutput, int fileWriteTimes, int fileReadTimes) throws IOException { 
    for (String line : exepctedFileContentOutput){ 
**Line153**      Mockito.verify(mockPrintWriter, Mockito.times(fileWriteTimes)).print(line); 
    } 

    PowerMockito.verifyStatic(Mockito.times(fileReadTimes)); 
    FileUtils.lineIterator(FILTERED_IMAGE_DATA_TEXT_FILE, StandardCharsets.UTF_8.displayName()); 
} 

} 

我在嘲笑一个新的PrintWriter的运算符也是使用beans注入的。我在做什么错误？我很久没有接受这个错误了吗？ 任何帮助表示赞赏。

更新：

我建议以下变化和更新的代码，但现在我得到的错误：

Wanted but not invoked: mockPrintWriter.print("ASIN2 url1 "); -> 
at softlines.ctl.ruleExecutor.tasks.ProcessImageDataTest.verify‌​(ProcessImageDataTes‌​t.java:153) 
However, there were other interactions with this mock: -> at softlines.ctl.ruleExecutor.tasks.ProcessImageData.execute(Pr‌​ocessImageData.java:‌​51) -> 
at softlines.ctl.ruleExecutor.tasks.ProcessImageData.execute(Pr‌​ocessImageData.java:‌​51) -> 
at softlines.ctl.ruleExecutor.tasks.ProcessImageData.execute(Pr‌​ocessImageData.java:‌​58) – 

Answer 1

我看到在您的测试3个问题：

1. 你不要试图嘲笑正确的构造，确实是在方法execute，创建您PrintWriter与只有一个File类型的参数而您尝试模拟构造函数与2个参数类型File和String类型中的另一个。

因此，代码而应是：

PowerMockito.whenNew(PrintWriter.class) 
    .withArguments(IMAGE_FILE) 
    .thenReturn(mockPrintWriter); 

为了能够嘲笑你需要准备的类创建它是实例的构造在这种情况下为ProcessImageData，所以您需要在注释@PrepareForTest中添加ProcessImageData.class。（我不确定那里需要ProcessImageDataTest.class）

该字段lineIterator应注明@Mock。

而是用一个新行验证print的，应当验证直接println没有新线它是非常不容易出错。

---

我简化你的代码显示的想法。

假设ProcessImageData是：然后

public class ProcessImageData { 

    private final File newImageDataTextFile; 

    public ProcessImageData(final File newImageDataTextFile) { 
     this.newImageDataTextFile = newImageDataTextFile; 
    } 

    public void execute() throws Exception{ 
     try (PrintWriter writer = new PrintWriter(newImageDataTextFile)) { 
      LineIterator inputFileIterator = FileUtils.lineIterator(
       newImageDataTextFile, StandardCharsets.UTF_8.displayName() 
      ); 
      while (inputFileIterator.hasNext()) { 
       writer.println(inputFileIterator.nextLine()); 
      } 
     } 
    } 
} 

我的单元测试是：

@RunWith(PowerMockRunner.class) 
@PrepareForTest({ProcessImageData.class, FileUtils.class}) 
public class ProcessImageDataTest { 

    private File file = new File("imageFilePath"); 

    private ProcessImageData processImageData; 
    @Mock 
    private PrintWriter mockPrintWriter; 
    @Mock 
    private LineIterator lineIterator; 

    @Before 
    public void init() throws Exception { 
     MockitoAnnotations.initMocks(this); 

     processImageData = new ProcessImageData(file); 
     PowerMockito.whenNew(PrintWriter.class) 
      .withArguments(file) 
      .thenReturn(mockPrintWriter); 
     PowerMockito.mockStatic(FileUtils.class); 
     PowerMockito.when(
      FileUtils.lineIterator(file, StandardCharsets.UTF_8.displayName()) 
     ).thenReturn(lineIterator); 
     PowerMockito.when(lineIterator.hasNext()).thenReturn(true, true, false); 
    } 

    @Test 
    public void testExecute() throws Exception { 
     PowerMockito.when(lineIterator.nextLine()).thenReturn("Foo", "Bar"); 
     processImageData.execute(); 
     Mockito.verify(mockPrintWriter, Mockito.times(1)).println("Foo"); 
     Mockito.verify(mockPrintWriter, Mockito.times(1)).println("Bar"); 
    } 
} 

欲了解更多详情，请参阅How to mock construction of new objects。

---

how can I add verification in unit test for writer.close?

的一种方法是简单地检查close()在被调用一次加入下一行到你的单元测试：

Mockito.verify(mockPrintWriter, Mockito.times(1)).close(); 

Answer 2

你的PrintWriter的施工模拟不匹配。你告诉PowerMockito来回报您的模拟像这样：

PowerMockito.whenNew(PrintWriter.class).withArguments(IMAGE_FILE , StandardCharsets.UTF_8.name()).thenReturn(mockPrintWriter); 

所以，你不得不说：

new PrintWriter(IMAGE_FILE, "UTF-8"); // 2 arguments 

但不是在被测试的代码你execute方法，你这样做：

PrintWriter writer = new PrintWriter(newImageDataTextFile); // only 1 argument 

因此，您需要更改PowerMockito withArguments子句，或者您需要将"UTF-8"添加到中的构造函数调用中方法。