diff --git a/crypto_sign/sphincs-shake256-128f-simple/clean/thash_shake256_simple.c b/crypto_sign/sphincs-shake256-128f-simple/clean/thash_shake256_simple.c
index 7c2cdb63..341c6fd3 100644
--- a/crypto_sign/sphincs-shake256-128f-simple/clean/thash_shake256_simple.c
+++ b/crypto_sign/sphincs-shake256-128f-simple/clean/thash_shake256_simple.c
@@ -1,9 +1,9 @@
 #include <stdint.h>
 #include <string.h>
 
-#include "thash.h"
 #include "address.h"
 #include "params.h"
+#include "thash.h"
 
 #include "fips202.h"
 
diff --git a/crypto_sign/sphincs-shake256-128f-simple/clean/wots.c b/crypto_sign/sphincs-shake256-128f-simple/clean/wots.c
index a6a8ada6..4431986d 100644
--- a/crypto_sign/sphincs-shake256-128f-simple/clean/wots.c
+++ b/crypto_sign/sphincs-shake256-128f-simple/clean/wots.c
@@ -1,11 +1,11 @@
 #include <stdint.h>
 #include <string.h>
 
-#include "utils.h"
 #include "address.h"
 #include "hash.h"
 #include "params.h"
 #include "thash.h"
+#include "utils.h"
 #include "wots.h"
 
 // TODO clarify address expectations, and make them more uniform.
diff --git a/test/helpers.py b/test/helpers.py
index 966510f1..18ac1e4f 100644
--- a/test/helpers.py
+++ b/test/helpers.py
@@ -30,8 +30,11 @@ def run_subprocess(command, working_dir='.', env=None, expected_returncode=0):
         env=env,
     )
     print(result.stdout.decode('utf-8'))
-    assert result.returncode == expected_returncode, \
-        "Got unexpected return code {}".format(result.returncode)
+    if expected_returncode is not None:
+        assert result.returncode == expected_returncode, \
+            "Got unexpected return code {}".format(result.returncode)
+    else:
+        return (result.returncode, result.stdout.decode('utf-8'))
     return result.stdout.decode('utf-8')
 
 
@@ -111,8 +114,10 @@ def permit_test(testname, thing, **args):
 
     if isinstance(thing, pqclean.Implementation):
         scheme = thing.scheme
-    else:
+    elif isinstance(thing, pqclean.Scheme):
         scheme = thing
+    else:
+        return True
 
     if 'PQCLEAN_ONLY_TYPES' in os.environ:
         if not(scheme.type.lower() in os.environ['PQCLEAN_ONLY_TYPES'].lower().split(',')):
diff --git a/test/pqclean.py b/test/pqclean.py
index d11b1bce..12e1d61d 100644
--- a/test/pqclean.py
+++ b/test/pqclean.py
@@ -70,7 +70,7 @@ class Implementation:
     def __init__(self, scheme, name):
         self.scheme = scheme
         self.name = name
-        
+
     def metadata(self):
         for i in self.scheme.metadata()['implementations']:
             if i['name'] == self.name:
@@ -79,9 +79,6 @@ class Implementation:
     def path(self, base='..') -> str:
         return os.path.join(self.scheme.path(), self.name)
 
-    def namespace_prefix(self):
-        return 'PQCLEAN_{}_{}_'.format(self.scheme.name.upper(), self.name.upper()).replace('-', '')
-
     def libname(self) -> str:
         if os.name == 'nt':
             return "lib{}_{}.lib".format(self.scheme.name, self.name)
diff --git a/test/test_common.py b/test/test_common.py
index 3640bb3f..e4c89939 100644
--- a/test/test_common.py
+++ b/test/test_common.py
@@ -12,7 +12,7 @@ import helpers
 def test_common():
     for d in os.listdir('common'):
         primitive = re.sub(r"\.c$", "", d)
-        yield check_common, primitive
+        if helpers.permit_test('common', None): yield check_common, primitive
 
 
 def check_common(primitive):
diff --git a/test/test_linter.py b/test/test_linter.py
index 07e01180..e73492d5 100644
--- a/test/test_linter.py
+++ b/test/test_linter.py
@@ -1,6 +1,7 @@
 import os
 from glob import glob
 import sys
+import unittest
 
 import pqclean
 import helpers
@@ -17,18 +18,26 @@ def test_clang_tidy():
 
 def check_tidy(implementation: pqclean.Implementation):
     helpers.ensure_available('clang-tidy')
-    cfiles = glob(os.path.join(implementation.path(), '*.c'))
+    cfiles = implementation.cfiles()
     common_files = glob(os.path.join('..', 'common', '*.c'))
-    helpers.run_subprocess(['clang-tidy',
-                    '-quiet',
-                    '-header-filter=.*'] +
-                     additional_flags +
-                    [*cfiles,
-                    *common_files,
-                    '--',
-                    '-iquote', os.path.join('..', 'common'),
-                    '-iquote', implementation.path(),
-                    ])
+    (returncode, _) = helpers.run_subprocess(
+        ['clang-tidy',
+         '-quiet',
+         '-header-filter=.*',
+         *additional_flags,
+         *cfiles,
+         *common_files,
+         '--',
+         '-iquote', os.path.join('..', 'common'),
+         '-iquote', implementation.path()],
+        expected_returncode=None,
+    )
+
+    # Detect and gracefully avoid segfaults
+    if returncode == -11:
+        raise unittest.SkipTest("clang-tidy segfaulted")
+    else:
+        assert returncode == 0, "Clang-tidy returned %d" % returncode
 
 
 if __name__ == "__main__":