Add flake8 linter and fix linter issues

flake8 with bugbear plugin

Author: prmtl

.travis.yml

@@ -32,5 +32,5 @@ matrix:
       python: 3.8-dev
       dist: xenial
       sudo: true
-    - env: TOXENV=py36-lint
+    - env: TOXENV=lint
       python: 3.6

pydot_ng/__init__.py

@@ -1246,7 +1246,7 @@ def get_node_list(self):
         """
         node_objs = list()
 
-        for node, obj_dict_list in self.obj_dict['nodes'].items():
+        for obj_dict_list in self.obj_dict['nodes'].values():
             node_objs.extend([
                 Node(obj_dict=obj_d)
                 for obj_d
@@ -1362,7 +1362,7 @@ def get_edge_list(self):
         """
         edge_objs = list()
 
-        for edge, obj_dict_list in self.obj_dict['edges'].items():
+        for obj_dict_list in self.obj_dict['edges'].values():
             edge_objs.extend([
                 Edge(obj_dict=obj_d)
                 for obj_d
@@ -1428,7 +1428,7 @@ def get_subgraph_list(self):
 
         sgraph_objs = list()
 
-        for sgraph, obj_dict_list in self.obj_dict['subgraphs'].items():
+        for obj_dict_list in self.obj_dict['subgraphs'].values():
             sgraph_objs.extend([
                 Subgraph(obj_dict=obj_d)
                 for obj_d
@@ -1508,7 +1508,7 @@ def to_string(self):
             for obj
             in (edge_obj_dicts + node_obj_dicts + sgraph_obj_dicts)])
 
-        for idx, obj in obj_list:
+        for _idx, obj in obj_list:
             if obj['type'] == 'node':
                 node = Node(obj_dict=obj)
 

pydot_ng/_dotparser.py

@@ -134,7 +134,7 @@ def update_parent_graph_hierarchy(g, parent_graph=None, level=0):
                         obj['parent_graph'].set_parent_graph(parent_graph)
 
                 if key_name == 'edges' and len(key) == 2:
-                    for idx, vertex in enumerate(obj['points']):
+                    for vertex in obj['points']:
                         if isinstance(vertex, (pydot.Graph, pydot.Subgraph,
                                                pydot.Cluster)):
                             vertex.set_parent_graph(parent_graph)
@@ -162,7 +162,7 @@ def add_elements(g, toks, defaults_graph=None, defaults_node=None,
     if defaults_edge is None:
         defaults_edge = {}
 
-    for elm_idx, element in enumerate(toks):
+    for element in toks:
         if isinstance(element, (pydot.Subgraph, pydot.Cluster)):
             add_defaults(element, defaults_graph)
             g.add_subgraph(element)

test/test_pydot.py

@@ -8,9 +8,7 @@
 from __future__ import division
 from __future__ import print_function
 
-from hashlib import sha256
 import os
-import subprocess
 import sys
 
 import pydot_ng as pydot

tox.ini

@@ -9,11 +9,21 @@ commands = py.test -v {posargs:test/}
 
 [testenv:lint]
 deps =
-  flake8==3.5.0
+  flake8
+  flake8-bugbear
 skip_install = True
-commands = flake8
+commands =
+  flake8
 
 
 [flake8]
 show-source = true
-max-line-length = 99
+max-line-length = 79
+exclude =
+    .git,
+    .tox,
+    .mypy_cache,
+    .pytest_cache,
+    __pycache__,
+    build,
+    dist