FTPFS: Test fix - move opener unit test for FTPS into its own function.

Author: odgalvin

tests/test_opener.py

@@ -302,6 +302,9 @@ def test_open_ftp(self, mock_FTPFS):
         mock_FTPFS.assert_called_once_with(
             "ftp.example.org", passwd="bar", port=21, user="foo", proxy=None, timeout=10, tls=False
         )
+
+    @mock.patch("fs.ftpfs.FTPFS")
+    def test_open_ftps(self, mock_FTPFS):
         open_fs("ftps://foo:bar@ftp.example.org")
         mock_FTPFS.assert_called_once_with(
             "ftp.example.org", passwd="bar", port=21, user="foo", proxy=None, timeout=10, tls=True