iotests: Remove Python 2 compatibility code

Some scripts check the Python version number and have two code paths to
accomodate both Python 2 and 3. Remove the code specific to Python 2 and
assert the minimum version of 3.6 instead (check skips Python tests in
this case, so the assertion would only ever trigger if a Python script
is executed manually).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

tests/qemu-iotests/044

@@ -28,9 +28,6 @@ import struct
 import subprocess
 import sys
 
-if sys.version_info.major == 2:
-    range = xrange
-
 test_img = os.path.join(iotests.test_dir, 'test.img')
 
 class TestRefcountTableGrowth(iotests.QMPTestCase):

tests/qemu-iotests/163

@@ -21,9 +21,6 @@
 import os, random, iotests, struct, qcow2, sys
 from iotests import qemu_img, qemu_io, image_size
 
-if sys.version_info.major == 2:
-    range = xrange
-
 test_img = os.path.join(iotests.test_dir, 'test.img')
 check_img = os.path.join(iotests.test_dir, 'check.img')
 

tests/qemu-iotests/iotests.py

@@ -35,6 +35,7 @@ from collections import OrderedDict
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
 from qemu import qtest
 
+assert sys.version_info >= (3,6)
 
 # This will not work if arguments contain spaces but is necessary if we
 # want to support the override options that ./check supports.
@@ -250,10 +251,7 @@ def image_size(img):
     return json.loads(r)['virtual-size']
 
 def is_str(val):
-    if sys.version_info.major >= 3:
-        return isinstance(val, str)
-    else:
-        return isinstance(val, str) or isinstance(val, unicode)
+    return isinstance(val, str)
 
 test_dir_re = re.compile(r"%s" % test_dir)
 def filter_test_dir(msg):
@@ -935,12 +933,7 @@ def execute_test(test_function=None,
     else:
         # We need to filter out the time taken from the output so that
         # qemu-iotest can reliably diff the results against master output.
-        if sys.version_info.major >= 3:
-            output = io.StringIO()
-        else:
-            # io.StringIO is for unicode strings, which is not what
-            # 2.x's test runner emits.
-            output = io.BytesIO()
+        output = io.StringIO()
 
     logging.basicConfig(level=(logging.DEBUG if debug else logging.WARN))