Switch free check to Python test suite

.travis/free-check.sh

@@ -1,37 +0,0 @@
-#!/bin/bash
-
-###
-# Checks that "free" is not used unprotected in the main OQS code.
-###
-
-set -e
-
-source $(dirname $0)/defs.sh
-
-RET=0
-
-# We need to temporarily remove bash fail-on-error for the last command, because grep returns with error code 1 when there are no lines found
-set +e
-FREE=$(find src -name '*.c' | grep -v upstream | grep -v 'picnic/external' | xargs grep '[^_]free' | grep "free(" | grep -v 'IGNORE free-check')
-ERROR_CODE=$?
-set -e
-
-if [ ${ERROR_CODE} -ne 1 ];
-then
-	${PRINT_RED}
-	echo "'free' is used in the following non-upstream files.  These should be changed to 'OQS_MEM_secure_free' or 'OQS_MEM_insecure_free' as appropriate.";
-	${PRINT_RESET}
-	echo -n ${FREE} | tr ';' '\n' | sed -e 's/^ //'
-	${PRINT_RED}
-	echo "If you are sure you want to use 'free' in a particular spot, add the comment"
-	echo "    // IGNORE free-check"
-	echo "on the line where 'free' occurs."
-	${PRINT_RESET}
-	RET=1
-else
-	${PRINT_GREEN}
-	echo "No uses of 'free' detected in non-upstream files.";
-	${PRINT_RESET}
-fi;
-
-exit ${RET}

tests/helpers.py

@@ -48,8 +48,9 @@ def run_subprocess(command, working_dir='.', env=None, expected_returncode=0, in
         cwd=working_dir,
         env=env,
     )
-    print(stdout.decode('utf-8'))
+    if retcode != expected_returncode:
-    assert retcode == expected_returncode, "Got unexpected return code {}".format(retcode)
+        print(stdout.decode('utf-8'))
+        assert False, "Got unexpected return code {}".format(retcode)
     return stdout.decode('utf-8')
 
 def available_kems_by_name():

tests/test_lint.py

@@ -0,0 +1,28 @@
+import helpers
+import os
+import os.path
+import pytest
+import sys
+
+###
+# Checks that "free" is not used unprotected in the main OQS code.
+###
+@helpers.filtered_test
+@pytest.mark.skipif(sys.platform.startswith("win"), reason="Not needed on Windows")
+def test_free():
+    files = helpers.run_subprocess(['find', 'src', '-name', '*.c'])
+    files = helpers.run_subprocess(['grep', '-v', 'picnic/external'], input=files.encode('utf8'))
+    lines = helpers.run_subprocess(['xargs', 'grep', '[^_]free('], input=files.encode('utf8'))
+    lines = lines.split("\n")
+    okay = True
+    for line in lines:
+        if line == "": continue
+        if not('IGNORE free-check' in line):
+            okay = False
+            print("Suspicious `free` in " + line)
+    assert okay, "'free' is used in some files.  These should be changed to 'OQS_MEM_secure_free' or 'OQS_MEM_insecure_free' as appropriate. If you are sure you want to use 'free' in a particular spot, add the comment '// IGNORE free-check' on the line where 'free' occurs."
+
+if __name__ == "__main__":
+    import sys
+    pytest.main(sys.argv)
+