env: refactor imports in cmd/env.py and tests

lib/spack/spack/cmd/env.py

@@ -3,9 +3,13 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-import llnl.util.tty as tty
+import os
-import spack
+import sys
-import llnl.util.filesystem as fs
+import shutil
+import argparse
+from contextlib import contextmanager
+from six.moves import zip_longest
+
 import spack.modules
 import spack.util.spack_json as sjson
 import spack.util.spack_yaml as syaml
@@ -20,16 +24,9 @@
 from spack.spec import Spec, CompilerSpec, FlagMap
 from spack.repo import Repo
 from spack.version import VersionList
-from contextlib import contextmanager
 
-import argparse
+import llnl.util.tty as tty
-try:
+import llnl.util.filesystem as fs
-    from itertools import izip_longest as zip_longest
-except ImportError:
-    from itertools import zip_longest
-import os
-import sys
-import shutil
 
 description = "group a subset of packages"
 section = "environment"

lib/spack/spack/test/cmd/env.py

@@ -6,11 +6,9 @@
 import unittest
 import tempfile
 import shutil
+from six import StringIO
+
 import pytest
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
 
 import spack.cmd.env
 import spack.modules