Ensure tests get different names by adding an ordinal

ddt.py

@@ -4,7 +4,7 @@
 import re
 from functools import wraps
 
-__version__ = '0.7.1'
+__version__ = '0.8.0'
 
 # These attributes will not conflict with any real python attribute
 # They are added to the decorated test method and processed later
@@ -62,18 +62,21 @@ def wrapper(func):
     return wrapper
 
 
-def mk_test_name(name, value):
+def mk_test_name(name, value, index=0):
     """
-    Generate a new name for the test named ``name``, appending ``value``.
+    Generate a new name for a test case.
+
+    It will take the original test name and append an ordinal index and a
+    string representation of the value, and convert the result into a valid
+    python identifier by replacing extraneous characters with ``_``.
 
     """
     try:
-        test_name = "{0}_{1}".format(name, value)
+        value = str(value)
     except UnicodeEncodeError:
         # fallback for python2
-        test_name = "{0}_{1}".format(
-            name, value.encode('ascii', 'backslashreplace')
-        )
+        value = value.encode('ascii', 'backslashreplace')
+    test_name = "{0}_{1}_{2}".format(name, index + 1, value)
     return re.sub('\W|^(?=\d)', '_', test_name)
 
 
@@ -87,21 +90,20 @@ def ddt(cls):
     For each method decorated with ``@data``, this will effectively create as
     many methods as data items are passed as parameters to ``@data``.
 
-    The names of the test methods follow the pattern ``test_func_name
-    + "_" + str(data)``. If ``data.__name__`` exists, it is used
-    instead for the test method name.
+    The names of the test methods follow the pattern
+    ``original_test_name_{ordinal}_{data}``. ``ordinal`` is the position of the
+    data argument, starting with 1.
+
+    For data we use a string representation of the data value converted into a
+    valid python identifier.  If ``data.__name__`` exists, we use that instead.
 
     For each method decorated with ``@file_data('test_data.json')``, the
     decorator will try to load the test_data.json file located relative
     to the python file containing the method that is decorated. It will,
     for each ``test_name`` key create as many methods in the list of values
     from the ``data`` key.
 
-    The names of these test methods follow the pattern of
-    ``test_name`` + str(data)``
-
     """
-
     def feed_data(func, new_name, *args, **kwargs):
         """
         This internal method decorator feeds the test data item to the test.
@@ -139,19 +141,19 @@ def _raise_ve(*args):
             add_test(test_name, _raise_ve, None)
         else:
             data = json.loads(open(data_file_path).read())
-            for elem in data:
+            for i, elem in enumerate(data):
                 if isinstance(data, dict):
                     key, value = elem, data[elem]
-                    test_name = mk_test_name(name, key)
+                    test_name = mk_test_name(name, key, i)
                 elif isinstance(data, list):
                     value = elem
-                    test_name = mk_test_name(name, value)
+                    test_name = mk_test_name(name, value, i)
                 add_test(test_name, func, value)
 
     for name, func in list(cls.__dict__.items()):
         if hasattr(func, DATA_ATTR):
-            for v in getattr(func, DATA_ATTR):
-                test_name = mk_test_name(name, getattr(v, "__name__", v))
+            for i, v in enumerate(getattr(func, DATA_ATTR)):
+                test_name = mk_test_name(name, getattr(v, "__name__", v), i)
                 if hasattr(func, UNPACK_ATTR):
                     if isinstance(v, tuple) or isinstance(v, list):
                         add_test(test_name, func, *v)

docs/example.rst

@@ -38,3 +38,7 @@ And then run them with your favourite test runner, e.g. if you use nose::
 
 The number of test cases actually run and reported separately has been
 multiplied.
+
+
+DDT will try to give the new test cases meaningful names by converting the
+data values to valid python identifiers.

test/test_functional.py

@@ -130,7 +130,8 @@ def test_file_data_test_names_dict():
     test_data_path = os.path.join(tests_dir, 'test_data_dict.json')
     test_data = json.loads(open(test_data_path).read())
     created_tests = set([
-        "test_something_again_{0}".format(name) for name in test_data.keys()
+        "test_something_again_{0}_{1}".format(index + 1, name)
+        for index, name in enumerate(test_data.keys())
     ])
 
     assert_equal(tests, created_tests)
@@ -201,8 +202,8 @@ class mytest(object):
     setattr(mytest, 'test_hello', data_hello)
 
     ddt_mytest = ddt(mytest)
-    assert_is_not_none(getattr(ddt_mytest, 'test_hello_data1'))
-    assert_is_not_none(getattr(ddt_mytest, 'test_hello_2'))
+    assert_is_not_none(getattr(ddt_mytest, 'test_hello_1_data1'))
+    assert_is_not_none(getattr(ddt_mytest, 'test_hello_2_2'))
 
 
 def test_ddt_data_unicode():
@@ -223,10 +224,9 @@ class mytest(object):
             def test_hello(self, val):
                 pass
 
-        assert_is_not_none(getattr(mytest, 'test_hello_ascii'))
-        assert_is_not_none(getattr(mytest, 'test_hello_non_ascii__u2603'))
-        assert_is_not_none(
-            getattr(mytest, """test_hello__u__u2603____data__"""))
+        assert_is_not_none(getattr(mytest, 'test_hello_1_ascii'))
+        assert_is_not_none(getattr(mytest, 'test_hello_2_non_ascii__u2603'))
+        assert_is_not_none(getattr(mytest, 'test_hello_3__u__u2603____data__'))
 
     elif six.PY3:
 
@@ -236,10 +236,9 @@ class mytest(object):
             def test_hello(self, val):
                 pass
 
-        assert_is_not_none(getattr(mytest, 'test_hello_ascii'))
-        assert_is_not_none(getattr(mytest, 'test_hello_non_ascii__'))
-        assert_is_not_none(
-            getattr(mytest, """test_hello________data__"""))
+        assert_is_not_none(getattr(mytest, 'test_hello_1_ascii'))
+        assert_is_not_none(getattr(mytest, 'test_hello_2_non_ascii__'))
+        assert_is_not_none(getattr(mytest, 'test_hello_3________data__'))
 
 
 def test_feed_data_with_invalid_identifier():
@@ -251,6 +250,8 @@ def test_feed_data_with_invalid_identifier():
 
     obj = DummyInvalidIdentifier()
     method = getattr(obj, tests[0])
-    assert_equal(method.__name__,
-                 'test_data_with_invalid_identifier_32v2_g__Gmw845h_W_b53wi_')
+    assert_equal(
+        method.__name__,
+        'test_data_with_invalid_identifier_1_32v2_g__Gmw845h_W_b53wi_'
+    )
     assert_equal(method(), '32v2 g #Gmw845h$W b53wi.')

tox.ini

@@ -9,14 +9,15 @@ deps =
     flake8
     six
 commands = 
-    nosetests --with-coverage --cover-package=ddt --cover-html
+    nosetests -s --with-coverage --cover-package=ddt --cover-html
     flake8 ddt.py test
 
 [testenv:py27]
 deps =
     {[testenv]deps}
     Sphinx
+    sphinxcontrib-programoutput
 commands = 
-    nosetests --with-coverage --cover-package=ddt --cover-html
+    nosetests -s --with-coverage --cover-package=ddt --cover-html
     flake8 ddt.py test
     sphinx-build -b html docs docs/_build