Tries deleting a normal file (as opposed to a directory, symlink, etc).
function testUnused() {
$file = $this
->createFile();
// Check that deletion removes the file and database record.
$this
->assertTrue(is_file($file->uri), t('File exists.'));
$file
->delete();
$this
->assertFileHooksCalled(array(
'delete',
));
$this
->assertFalse(file_exists($file->uri), t('Test file has actually been deleted.'));
$this
->assertFalse(file_load($file->fid), t('File was removed from the database.'));
}