Add "fix-lint" tox environment to fix linting errors

CONTRIBUTING.rst

@@ -212,7 +212,12 @@ but here is a simple overview:
     $ tox -e linting,py27,py36
 
    This command will run tests via the "tox" tool against Python 2.7 and 3.6
-   and also perform "lint" coding-style checks.
+   and also perform "lint" coding-style checks. If you have too much linting errors,
+   try running::
+
+    $ tox -e fix-lint
+
+   To fix pep8 related errors. 
 
 #. You can now edit your local working copy.
 

changelog/2582.trivial

@@ -0,0 +1 @@
+Added ``fix-lint`` tox environment to run automatic pep8 fixes on the code.

testing/code/test_source.py

@@ -335,21 +335,6 @@ def test_getstartingblock_singleline():
     assert len(l) == 1
 
 
-def test_getstartingblock_multiline():
-    class A(object):
-        def __init__(self, *args):
-            frame = sys._getframe(1)
-            self.source = _pytest._code.Frame(frame).statement
-
-    x = A('x',
-          'y'
-          ,
-          'z')
-
-    l = [i for i in x.source.lines if i.strip()]
-    assert len(l) == 4
-
-
 def test_getline_finally():
     def c(): pass
     excinfo = pytest.raises(TypeError, """

testing/code/test_source_multiline_block.py

@@ -0,0 +1,26 @@
+# flake8: noqa
+import sys
+
+import _pytest._code
+
+
+def test_getstartingblock_multiline():
+    """
+    This test was originally found in test_source.py, but it depends on the weird
+    formatting of the ``x = A`` construct seen here and our autopep8 tool can only exclude entire
+    files (it does not support excluding lines/blocks using the traditional #noqa comment yet,
+    see hhatto/autopep8#307). It was considered better to just move this single test to its own
+    file and exclude it from autopep8 than try to complicate things.
+    """
+    class A(object):
+        def __init__(self, *args):
+            frame = sys._getframe(1)
+            self.source = _pytest._code.Frame(frame).statement
+
+    x = A('x',
+          'y'
+          ,
+          'z')
+
+    l = [i for i in x.source.lines if i.strip()]
+    assert len(l) == 4

testing/test_capture.py

@@ -288,7 +288,7 @@ class TestLoggingInteraction(object):
                 stream.close() # to free memory/release resources
         """)
         result = testdir.runpytest_subprocess(p)
-        result.stderr.str().find("atexit") == -1
+        assert result.stderr.str().find("atexit") == -1
 
     def test_logging_and_immediate_setupteardown(self, testdir):
         p = testdir.makepyfile("""

tox.ini

@@ -149,6 +149,14 @@ commands =
     rm -rf /tmp/doc-exec*
     make regen
 
+[testenv:fix-lint]
+skipsdist = True
+usedevelop = True
+deps =
+    autopep8
+commands =
+    autopep8 --in-place -r --max-line-length=120 --exclude=vendored_packages,test_source_multiline_block.py _pytest testing
+
 [testenv:jython]
 changedir = testing
 commands =