FileSystem to FTPFile []?

Question

I just want to know if there is a way to mock the FTPFile array. I am trying to pass a fake FTPFile [] as a parameter to the function I want to check:

protected void indexFolder(FTPClient, FTPFile[], File, FTPFolderAssetSource); 

I use FakeFtpServer to fake, as the name says, my ftp server. This library allows you to fake ftp content this way:

  fileSystem = new WindowsFakeFileSystem(); DirectoryEntry directoryEntry1 = new DirectoryEntry("c:\\"); directoryEntry1.setPermissions(new Permissions("rwxrwx---")); directoryEntry1.setOwner(USER1); FileEntry fileEntry1 = new FileEntry("c:\\data\\file1.txt", CONTENTS); fileEntry1.setPermissionsFromString("rw-rw-rw-"); fileEntry1.setOwner(USER1); fileEntry1.setGroup(GROUP); fileSystem.add(directoryEntry1); fileSystem.add(fileEntry1); ftp = new FakeFtpServer(); ftp.setFileSystem(fileSystem); 

Now, how can I use fileSystem to test my function, which requires FTPFile [] as a parameter?

Answer 1

There is nothing special in the FTPFile class that would prevent ridicule. Unfortunately, using Mockito, you cannot mock arrays because they are final.

This sample code should demonstrate the problem:

 import static org.mockito.Mockito.*; import org.junit.Test; public class TestMockArrays { interface Animal { String getName(); } @Test public void testMockArray() { final Animal[] mockArray = mock(Animal[].class); when(mockArray[0].getName()).thenReturn("cat"); when(mockArray[1].getName()).thenReturn("dog"); when(mockArray[2].getName()).thenReturn("fish"); print1st3(mockArray); } public static void print1st3(final Animal[] animals) { System.out.println(animals[0].getName() + " " + animals[1].getName() + " " + animals[2].getName()); } } 

Run it and you will see that this leads to an error message that clearly indicates a problem:

org.mockito.exceptions.base.MockitoException: Cannot mock class [LTestMockArrays $ Animal;

Mokito cannot taunt / spy on: - final classes - anonymous classes - primitive types

The easiest solution is to use an extension for Mockito, such as Powermock , which bypasses certain restrictions for Mockito mocking using bytecode manipulations. You can then create the mock array by adding the following annotations to your junit test class:

 @RunWith(PowerMockRunner.class) // Need to run with Powermock runner @PrepareForTest(FTPFile[].class) // We prepare FTPFile[] class for test because it final 

then in your testing method you will create a Mockito as usual:

 FTPFile[] mockFTPFiles = mock(FTPFile[].class);