diff --git a/doc/en/Makefile b/doc/en/Makefile
index 5b534da09..286bbd8e7 100644
--- a/doc/en/Makefile
+++ b/doc/en/Makefile
@@ -41,7 +41,7 @@ clean:
 	-rm -rf $(BUILDDIR)/*
 
 regen:
-	PYTHONDONTWRITEBYTECODE=1 PYTEST_ADDOPT=-p\	 no:hypothesis COLUMNS=76 regendoc --update *.rst */*.rst ${REGENDOC_ARGS}
+	PYTHONDONTWRITEBYTECODE=1 PYTEST_ADDOPT=-pno:hypothesis COLUMNS=76 regendoc --update *.rst */*.rst ${REGENDOC_ARGS}
 
 html:
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
diff --git a/doc/en/unittest.rst b/doc/en/unittest.rst
index 6ee7d505e..436e64e07 100644
--- a/doc/en/unittest.rst
+++ b/doc/en/unittest.rst
@@ -171,7 +171,8 @@ creation of a per-test temporary directory::
             tmpdir.join("samplefile.ini").write("# testdata")
 
         def test_method(self):
-            s = open("samplefile.ini").read() 
+            with open("samplefile.ini") as f:
+                s = f.read()
             assert "testdata" in s
 
 Due to the ``autouse`` flag the ``initdir`` fixture function will be
diff --git a/doc/en/warnings.rst b/doc/en/warnings.rst
index fb18c4a2f..64316cf6b 100644
--- a/doc/en/warnings.rst
+++ b/doc/en/warnings.rst
@@ -39,7 +39,7 @@ Running pytest now produces this output::
 The ``-W`` flag can be passed to control which warnings will be displayed or even turn
 them into errors::
 
-    $ pytest -q test_show_warning.py -W error::DeprecationWarning
+    $ pytest -q test_show_warnings.py -W error::DeprecationWarning
     
     no tests ran in 0.12 seconds
     ERROR: file not found: test_show_warning.py
diff --git a/tox.ini b/tox.ini
index 52bd471c4..a2d4af9ed 100644
--- a/tox.ini
+++ b/tox.ini
@@ -134,6 +134,7 @@ commands=
 
 [testenv:regen]
 changedir=doc/en
+skipsdist=True
 basepython = python3.5
 deps=sphinx
      PyYAML