RuleTest.java

public class RuleTest {
 
    @Rule
    public TemporaryFolder tmpFolder = new TemporaryFolder();
 
    @Test
    public void shouldCreateNewFileInTemporaryFolder() throws IOException {
        File created = tmpFolder.newFile("file.txt");
 
        assertTrue(created.isFile());
        assertEquals(tmpFolder.getRoot(), created.getParentFile());
    }
}