Adding code to anonymize fixture data

fixtures/anonymize_fixtures.py

+import sys
+import json
+import random
+import copy
+from collections import defaultdict
+from argparse import ArgumentParser, FileType
+
+
+def parse_args(args=sys.argv[1:]):
+    parser = ArgumentParser()
+    parser.add_argument('-d', '--data', type=FileType('r'), default=sys.stdin)
+    parser.add_argument('-o', '--output', type=FileType('w'), default=sys.stdout)
+    parser.add_argument('count', type=int)
+    return parser.parse_args(args)
+
+def main(args=sys.argv[1:]):
+    args = parse_args(args)
+
+    data = json.load(args.data)
+    unique_students = set(entry['fields']['student'] for entry in data)
+    if args.count > len(unique_students) * 0.1:
+        raise Exception("Can't be sufficiently anonymous selecting {count} of {unique} students".format(
+            count=args.count, unique=len(unique_students)))
+
+    by_problems = defaultdict(list)
+    for entry in data:
+        by_problems[entry['fields']['module_id']].append(entry)
+
+    out_data = []
+    out_pk = 1
+    for name, answers in by_problems.items():
+        for student_id in xrange(args.count):
+            sample = random.choice(answers)
+            data = copy.deepcopy(sample)
+            data["fields"]["student"] = student_id + 1
+            data["pk"] = out_pk
+            out_pk += 1
+            out_data.append(data)
+
+    json.dump(out_data, args.output, indent=2)
+
+if __name__ == "__main__":
+    sys.exit(main())