A possible fix for https://github.com/txels/ddt/issues/19

ddt.py

@@ -2,6 +2,7 @@ import inspect
 import json
 import os
 import re
+import sys
 from functools import wraps
 
 __version__ = '0.8.0'
@@ -70,7 +71,22 @@ def mk_test_name(name, value, index=0):
     string representation of the value, and convert the result into a valid
     python identifier by replacing extraneous characters with ``_``.
 
+    If hash randomization is enabled (a feature available since 2.7.3
+    and enabled by default since 3.3) and a non-scalar value is passed
+    this will omit the name argument by default. Set `PYTHONHASHSEED`
+    to a fixed value before running tests in these cases to get the
+    names back consistently.
+
     """
+
+    print(sys.flags)
+
+    if sys.hexversion >= 0x02070300 and \
+            sys.flags.hash_randomization and \
+            'PYTHONHASHSEED' not in os.environ and \
+            not isinstance(value, (type(None), str, int, float)):
+        return "{0}_{1}".format(name, index + 1)
+
     try:
         value = str(value)
     except UnicodeEncodeError:

docs/example.rst

@@ -42,3 +42,16 @@ multiplied.
 
 DDT will try to give the new test cases meaningful names by converting the
 data values to valid python identifiers.
+
+
+.. note::
+
+   Python 2.7.3 introduced *hash randomization* which is by default
+   enabled on Python 3.3 and later. DDT's default mechanism to
+   generate meaningful test names will **not** use the test data value
+   as part of the name for complex types if hash randomization is
+   enabled.
+
+   You can disable hash randomization by setting the
+   ``PYTHONHASHSEED`` environment variable to a fixed value before
+   running tests (``export PYTHONHASHSEED=1`` for example).

test/test_functional.py

@@ -1,5 +1,6 @@
 import os
 import json
+import sys
 
 import six
 
@@ -238,6 +239,9 @@ def test_ddt_data_unicode():
 
         assert_is_not_none(getattr(mytest, 'test_hello_1_ascii'))
         assert_is_not_none(getattr(mytest, 'test_hello_2_non_ascii__'))
+        if sys.hexversion >= 0x03030300 and 'PYTHONHASHSEED' not in os.environ:
+            assert_is_not_none(getattr(mytest, 'test_hello_3'))
+        else:
             assert_is_not_none(getattr(mytest, 'test_hello_3________data__'))