[misc] Python3 support, Github CI and QA Checks

[purhan]

Closes #50, closes #49, closes #52, closes #55, closes #61

[pandafy]

I believe it will work after rebasing on current master.

[pandafy]

Here is my initial review. I will look up the code again to see if anything got left out.

@purhan it will be easier for you later to squash commits later if you keep commits on this PR atomic. Remember we will merge 4 commits in the end.

[pandafy]

This is an issue with mock library and is fixed in python 3.8. Should we use python 3.8, or look for a workaround?

We should look for a workaround for now since rest of OpenWISP currently supports Python 3.6 and 3.7.
A possible workaround will be to catch the RuntimeError in tearDown:

diff --git a/tests/test_snmp/test_airos.py b/tests/test_snmp/test_airos.py
index 56234d0..fc190e2 100644
--- a/tests/test_snmp/test_airos.py
+++ b/tests/test_snmp/test_airos.py
@@ -168,4 +168,7 @@ class TestSNMPAirOS(unittest.TestCase, MockOutputMixin):
         self.assertIsInstance(self.device.uptime_tuple, tuple)
 
     def tearDown(self):
-        self.getcmd_patcher.stop()
+        try:
+            self.getcmd_patcher.stop()
+        except RuntimeError:
+            return

Don't forget to add a comment stating why this has been done and to remove it once support for Python 3.8 an above is added.

[nemesifier]

shall we update this since we are here or shall we do this later?

[purhan]

I think it may be better to do this in #56
Or we can do this here, what would you suggest changing this to?

[nemesifier]

Ok for #56

[pandafy]

• Add .coveragerc in this PR.
• Convert all " to ' in Python code except for doc strings.
• Swap out print statements with logger in this PR.

@purhan ensure that goals of #49 are met (check issue description)

[pandafy]

• Add .coveragerc in this PR.
• Convert all " to ' in Python code except for doc strings.
• Swap out print statements with logger in this PR.

@purhan ensure that goals of #49 are met (check issue description)

[purhan]

Note: We have to configure the coveralls bot to comment on PRs.

[nemesifier]

I made sure coveralls is enabled: https://coveralls.io/github/openwisp/netengine.
I left one minor request regarding link 404 verification, see below.

[pandafy]

LGTM! 👍🏼

Deferring merge to @nemesisdesign

[nemesifier]

@purhan LGTM!

I don't think squashing everything in one commit will be good, can you squash commits so we have one commit closing each issue mentioned?

[nemesifier]

Great 👍