PowerMockito doReturn null object-CodePudding

I have this code that works fine.


public class MyClass implements Serializable {
 
...
 
private UploadedFile uploadedFile;  
     
public UploadedFile getUploadedFile() {
     return uploadedFile; 
}
 
public void setUploadedFile(UploadedFile uploadedFile) {
    this.uploadedFile = uploadedFile;
}
 
public void fileRead(){
    ...
    Scanner scanner = new Scanner(uploadedFile.getInputStream());
    while (scanner.hasNextLine()) { ...}
    ...
 
}

Now I want to create a test for it. The problem is that when I run the test code below, uploadedFile is null when it gets to the the Scanner line. What do I need to change in the @Test method for uploadedFile not to be null in the Scanner line?


@Test
public void emptyFileTest() throws Exception {   
    ...
    UploadedFile uploadedFile = Mockito.mock(UploadedFile.class);
    PowerMockito.doReturn(new ByteArrayInputStream("".getBytes())).when(uploadedFile).getInputStream();    
    this.myClass.fileRead();
    ...
}

I also tried this, but with the same results.

PowerMockito.when(uploadedFile.getInputStream()).thenReturn(new ByteArrayInputStream("".getBytes()));

CodePudding user response：

Doesn't look like you set the uploadedFile variable in myClass

PowerMockito.doReturn(new ByteArrayInputStream("".getBytes())).when(uploadedFile).getInputStream();

You can do the same a bit easier: new ByteArrayInputStream(new byte[0]). There is no need to use a string to create an empty byte array.