Failing unit tests

[bjones1]

I've been putting a lot of effort into porting the preview plugin to use QWebEngine. I've now got almost everything working, but I'm seeing a failing in CI that seems unrelated. @andreikop, do you have time to take a look? See Travis and Appveyor runs. (This is on my branch).

======================================================================
FAIL: test_1 (test_plugins.test_lint.Test)
File is checked after opened
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Traceback (most recent call last):
  File "/home/travis/build/bjones1/enki/tests/test_lib/../test_plugins/test_lint.py", line 36, in test_1
    self.assertEqual(doc.qutepart.lintMarks, {})
AssertionError: {0: ('e', "F821 undefined name 'asdf'"), 1[37 chars]le')} != {}
+ {}
- {0: ('e', "F821 undefined name 'asdf'"),
-  1: ('w', 'W391 blank line at end of file')}

[andreikop]

I"ll try later today. But I'm not sure

[andreikop]

I've disabled tests which rely on flake8 output. Such a tests might behave different on different flake8 versions.

[bjones1]

Sounds good. Thanks for taking a look!