support/testing: switch to Python 3 only

Python 2.7 will not be maintained past 2020.

Many scripts on the tree are used during the build and should keep
Python 2 compatibility for a while.
This is not the case for the runtime test infra. It's meant to be run in
modern distros only, so it can safely switch to support Python 3 only.

An advantage of this approach is to have less scenarios to test in.
Otherwise every change to the test infra or runtime tests would need to
be tested against both versions of the interpreter, increasing the
effort of the developers, to ensure the compatibility to Python 2 was
not broken.

In order to accomplish the change to Python 3:
 - change the shebang for run-tests;
 - use Python 3 urllib as a drop-in replacement for Python 2 urllib2;
 - when writing the downloaded binary files, explicitly open the output
   file as binary;
 - when subprocess is used to retrieve the text output from commands,
   explicitly ask for text output. For this, use 'universal_newlines'
   because 'text' was added only on Python 3.7;
 - when pexpect is used to retrieve the text output from qemu or git,
   explicitly ask for text output using 'encoding';
 - the code using csv currently follows the example in the documentation
   for the Python 2 module, change it to follow the example in the
   documentation for the Python 3 module;
 - fix the relative import for test_git.py to be Python 3 compliant.

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Tested-by: Romain Naour <romain.naour@smile.fr>
Tested-by: Nicolas Carrier <nicolas.carrier@orolia.com>
Signed-off-by: Nicolas Carrier <nicolas.carrier@orolia.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

support/testing/infra/__init__.py

@@ -3,7 +3,8 @@ import re
 import sys
 import tempfile
 import subprocess
-from urllib2 import urlopen, HTTPError, URLError
+from urllib.request import urlopen
+from urllib.error import HTTPError, URLError
 
 ARTIFACTS_URL = "http://autobuild.buildroot.net/artefacts/"
 BASE_DIR = os.path.realpath(os.path.join(os.path.dirname(__file__), "../../.."))
@@ -44,7 +45,7 @@ def download(dldir, filename):
 
     try:
         url_fh = urlopen(os.path.join(ARTIFACTS_URL, filename))
-        with open(tmpfile, "w+") as tmpfile_fh:
+        with open(tmpfile, "w+b") as tmpfile_fh:
             tmpfile_fh.write(url_fh.read())
     except (HTTPError, URLError) as err:
         os.unlink(tmpfile)
@@ -60,7 +61,8 @@ def run_cmd_on_host(builddir, cmd):
     out = subprocess.check_output(cmd,
                                   stderr=open(os.devnull, "w"),
                                   cwd=builddir,
-                                  env={"LANG": "C"})
+                                  env={"LANG": "C"},
+                                  universal_newlines=True)
     return out
 
 

support/testing/infra/emulator.py

@@ -76,6 +76,7 @@ class Emulator(object):
         self.logfile.write("> starting qemu with '%s'\n" % " ".join(qemu_cmd))
         self.qemu = pexpect.spawn(qemu_cmd[0], qemu_cmd[1:],
                                   timeout=5 * self.timeout_multiplier,
+                                  encoding='utf-8',
                                   env={"QEMU_AUDIO_DRV": "none"})
         # We want only stdout into the log to avoid double echo
         self.qemu.logfile_read = self.logfile

support/testing/run-tests

@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 import argparse
 import sys
 import os

support/testing/tests/core/test_post_scripts.py

@@ -20,7 +20,7 @@ class TestPostScripts(infra.basetest.BRTest):
 
     def check_post_log_file(self, f, what, target_dir):
         lines = {}
-        with open(os.path.join(self.builddir, "build", f), 'rb') as csvfile:
+        with open(os.path.join(self.builddir, "build", f), newline='') as csvfile:
             r = csv.reader(csvfile, delimiter=',')
             for row in r:
                 lines[row[0]] = row[1]

support/testing/tests/download/gitremote.py

@@ -32,7 +32,8 @@ class GitRemote(object):
         for port in range(GIT_REMOTE_PORT_INITIAL, GIT_REMOTE_PORT_LAST + 1):
             cmd = daemon_cmd + ["--port={port}".format(port=port)]
             self.logfile.write("> starting git remote with '{}'\n".format(" ".join(cmd)))
-            self.daemon = pexpect.spawn(cmd[0], cmd[1:], logfile=self.logfile)
+            self.daemon = pexpect.spawn(cmd[0], cmd[1:], logfile=self.logfile,
+                                        encoding='utf-8')
             ret = self.daemon.expect(["Ready to rumble",
                                       "Address already in use"])
             if ret == 0:

support/testing/tests/download/test_git.py

@@ -1,7 +1,7 @@
 import os
 import shutil
 
-from gitremote import GitRemote
+from tests.download.gitremote import GitRemote
 
 import infra
 

support/testing/tests/utils/test_check_package.py

@@ -16,7 +16,8 @@ import infra
 def call_script(args, env, cwd):
     """Call a script and return stdout and stderr as lists."""
     out, err = subprocess.Popen(args, cwd=cwd, stdout=subprocess.PIPE,
-                                stderr=subprocess.PIPE, env=env).communicate()
+                                stderr=subprocess.PIPE, env=env,
+                                universal_newlines=True).communicate()
     return out.splitlines(), err.splitlines()