tools: Sort imports with isort & enforce linting via Travis.

This reformats import statements throughout the code as per isort, and
ensures the formatting is retained by adding the new linting script to
Travis.

Travis runs isort on the lowest python version, since the 'atomic'
option should ensure valid syntax, which is assumed to be compatible
with other supported versions.

Author: neiljp

.travis.yml

@@ -8,7 +8,9 @@ cache:
 matrix:
   include:
     - python: 3.5
-      name: "CPython 3.5 pytest (default linux)"
+      name: "CPython 3.5 pytest & isort linting (default linux)"
+      # Note that running isort on the lowest version should ensure changes are compatible
+      env: RUN_ISORT_CHECK=yes
     - python: 3.6
       name: "CPython 3.6 pytest & mypy type-checking (default linux)"
       env: RUN_MYPY=yes
@@ -30,6 +32,7 @@ install:
 script:
   - pipenv run pytest
   - if [[ "$RUN_MYPY" == "yes" ]]; then pipenv run pip install -r requirements.txt && pipenv run ./tools/run-mypy; fi
+  - if [[ "$RUN_ISORT_CHECK" == "yes" ]]; then pipenv run pip install -r requirements.txt && pipenv run ./tools/run-isort-check; fi
 after_success:
   - pip install codecov
   - codecov

setup.py

@@ -1,8 +1,10 @@
+import codecs
 import os
 import sys
-import codecs
-from setuptools import setup, find_packages
+
+from setuptools import find_packages, setup
 from setuptools.command.test import test as TestCommand
+
 from zulipterminal.version import ZT_VERSION
 
 

tests/cli/test_run.py

@@ -1,5 +1,6 @@
 import pytest
-from zulipterminal.cli.run import main, in_color, THEMES, get_login_id
+
+from zulipterminal.cli.run import THEMES, get_login_id, in_color, main
 from zulipterminal.model import ServerConnectionFailure
 from zulipterminal.version import ZT_VERSION
 

tests/config/test_keys.py

@@ -2,6 +2,7 @@
 
 from zulipterminal.config import keys
 
+
 AVAILABLE_COMMANDS = list(keys.KEY_BINDINGS.keys())
 
 USED_KEYS = {key

tests/config/test_themes.py

@@ -1,9 +1,10 @@
 import pytest
 
 from zulipterminal.config.themes import (
-    THEMES, required_styles, all_themes, complete_and_incomplete_themes
+    THEMES, all_themes, complete_and_incomplete_themes, required_styles,
 )
 
+
 expected_complete_themes = {
     'default', 'gruvbox', 'light', 'blue'
 }

tests/conftest.py

@@ -4,13 +4,11 @@
 
 import pytest
 
+from zulipterminal.helper import initial_index as helper_initial_index
 from zulipterminal.ui_tools.boxes import MessageBox
 from zulipterminal.ui_tools.buttons import (
-    StreamButton,
-    UserButton,
-    TopicButton,
+    StreamButton, TopicButton, UserButton,
 )
-from zulipterminal.helper import initial_index as helper_initial_index
 
 
 @pytest.fixture(autouse=True)

tests/core/test_core.py

@@ -6,6 +6,7 @@
 from zulipterminal.core import Controller
 from zulipterminal.version import ZT_VERSION
 
+
 CORE = "zulipterminal.core"
 
 

tests/helper/test_helper.py

@@ -1,13 +1,11 @@
+from typing import Any
+
 import pytest
 
 from zulipterminal.helper import (
-    index_messages,
+    canonicalize_color, classify_unread_counts, index_messages, notify,
     powerset,
-    classify_unread_counts,
-    canonicalize_color,
-    notify,
 )
-from typing import Any
 
 
 def test_index_messages_narrow_all_messages(mocker,

tests/model/test_model.py

@@ -4,8 +4,8 @@
 
 import pytest
 
-from zulipterminal.model import Model, ServerConnectionFailure
 from zulipterminal.helper import initial_index, powerset
+from zulipterminal.model import Model, ServerConnectionFailure
 
 
 class TestModel:

tests/ui/test_ui_tools.py

@@ -1,32 +1,22 @@
-import pytest
 import datetime
-from collections import defaultdict, OrderedDict
+from collections import OrderedDict, defaultdict
+
+import pytest
 from bs4 import BeautifulSoup
+from urwid import AttrWrap, Columns, Padding, Text
 
-from zulipterminal.ui_tools.views import (
-    MessageView,
-    MiddleColumnView,
-    StreamsView,
-    TopicsView,
-    UsersView,
-    RightColumnView,
-    LeftColumnView,
-    HelpView,
-    ModListWalker,
-    PopUpConfirmationView,
-    MsgInfoView,
-)
+from zulipterminal.config.keys import keys_for_command
+from zulipterminal.helper import powerset
 from zulipterminal.ui_tools.boxes import MessageBox
 from zulipterminal.ui_tools.buttons import (
-    TopButton,
-    StreamButton,
-    UserButton,
-    TopicButton,
+    StreamButton, TopButton, TopicButton, UserButton,
+)
+from zulipterminal.ui_tools.views import (
+    HelpView, LeftColumnView, MessageView, MiddleColumnView, ModListWalker,
+    MsgInfoView, PopUpConfirmationView, RightColumnView, StreamsView,
+    TopicsView, UsersView,
 )
-from zulipterminal.config.keys import keys_for_command
-from zulipterminal.helper import powerset
 
-from urwid import AttrWrap, Columns, Padding, Text
 
 VIEWS = "zulipterminal.ui_tools.views"
 TOPBUTTON = "zulipterminal.ui_tools.buttons.TopButton"