diff --git a/pkgs/development/python-modules/keyring/default.nix b/pkgs/development/python-modules/keyring/default.nix
index ce5bb315581d..2029eabba026 100644
--- a/pkgs/development/python-modules/keyring/default.nix
+++ b/pkgs/development/python-modules/keyring/default.nix
@@ -17,9 +17,7 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = [ entrypoints ] ++ stdenv.lib.optional stdenv.isLinux secretstorage;
 
-  # all tests with flake8 are broken right now
-  # https://github.com/tholo/pytest-flake8/issues/45
-  doCheck = false;
+  doCheck = !stdenv.isDarwin;
 
   checkPhase = ''
     py.test
diff --git a/pkgs/development/python-modules/pytest-flake8/default.nix b/pkgs/development/python-modules/pytest-flake8/default.nix
index b170f480e96e..c2d205f2833c 100644
--- a/pkgs/development/python-modules/pytest-flake8/default.nix
+++ b/pkgs/development/python-modules/pytest-flake8/default.nix
@@ -2,7 +2,7 @@
 
 buildPythonPackage rec {
   pname = "pytest-flake8";
-  version = "1.0.0";
+  version = "1.0.1";
 
   # although pytest is a runtime dependency, do not add it as
   # propagatedBuildInputs in order to allow packages depend on another version
@@ -12,7 +12,7 @@ buildPythonPackage rec {
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "01driw4sc6nfi3m3ii7d074pxi3h1h4mbiyad9crg5i1l5jxx5ir";
+    sha256 = "0s5fdivrmhjf6ybr6m2qb1h8hndv2jh2ir29qv36lhy9b7sc9kg5";
   };
 
   checkPhase = ''
diff --git a/pkgs/tools/security/vulnix/default.nix b/pkgs/tools/security/vulnix/default.nix
index b28fa7cfd475..dbb42c2bef42 100644
--- a/pkgs/tools/security/vulnix/default.nix
+++ b/pkgs/tools/security/vulnix/default.nix
@@ -9,9 +9,9 @@ pythonPackages.buildPythonApplication rec {
     sha256 = "0j6v6phq3naqnpvzxxnynsyv9y7bhig1gzvg594qpknqgyzj16bf";
   };
 
-  buildInputs =
-    [ ronn ] ++
-    (with pythonPackages; [ freezegun pytest pytestcov ]);
+  buildInputs = [ ronn ];
+
+  checkInputs = with pythonPackages; [ freezegun pytest pytestcov pytest-flake8 ];
 
   propagatedBuildInputs = [
     nix
@@ -27,11 +27,6 @@ pythonPackages.buildPythonApplication rec {
 
   outputs = [ "out" "doc" ];
 
-  # pytest-flake8 is currently broken
-  # re-enable after it has been fixed
-  # https://github.com/NixOS/nixpkgs/issues/39206
-  patches = [ ./disable-flake8.patch ];
-
   postBuild = ''
     make -C doc
   '';
diff --git a/pkgs/tools/security/vulnix/disable-flake8.patch b/pkgs/tools/security/vulnix/disable-flake8.patch
deleted file mode 100644
index cd165d05ccc1..000000000000
--- a/pkgs/tools/security/vulnix/disable-flake8.patch
+++ /dev/null
@@ -1,23 +0,0 @@
-diff --git a/setup.cfg b/setup.cfg
-index a9e37ce..41b9886 100644
---- a/setup.cfg
-+++ b/setup.cfg
-@@ -1,5 +1,5 @@
- [tool:pytest]
--addopts = --flake8 --tb=native --cov=src --cov-report=html --junitxml=report.xml -m 'not jenkinsonly' src/vulnix
-+addopts = --tb=native --cov=src --cov-report=html --junitxml=report.xml -m 'not jenkinsonly' src/vulnix
- markers = slow: This is a non-unit test and thus is not run by default. Use ``-m slow`` to run these, or ``-m 1`` to run all tests.
- 
- [aliases]
-diff --git a/setup.py b/setup.py
-index a9315e5..d14ad59 100644
---- a/setup.py
-+++ b/setup.py
-@@ -35,7 +35,6 @@ setup(
-             'freezegun>0.3',
-             'pytest>=3.2',
-             'pytest-cov>=2.5',
--            'pytest-flake8',
-             'pytest-runner>=2.11,<3dev',
-             'pytest-timeout>=1.2',
-             'setuptools_scm>=1.15',