How do I unit-test saving file to the disk with FileUtils?

Question

I know this variation has been asked before.

But, One of my functions is using Common's FileUtils . Here, it only takes File object and String. Is there any way to unit test this?

Answer 1

Of course. Use a temporary folder, save your file there, and delete the folder after the test.

If you use JUnit, look at the TemporaryFolder JUnit rule (it creates a temp folder for you and takes care of the deleting).

Example code:

public class YourTest {
  @Rule
  public TemporaryFolder folder= new TemporaryFolder();

  @Test
  public void testUsingTempFolder() throws IOException {
      String filePath = folder.newFile("myfile.txt").getAbsolutePath();
      FileUtils.writeFile(filePath, "some String");
      assertTrue(new File(filePath).exists());
  }
}