Remove DDT spec

DDT won't be introduced since it adds additional complexity (generated test
names) which should be avoided in the gate.

For more details see: https://review.openstack.org/#/c/223953/
Change-Id: Iaee81dfcef308d2a087dc42733250999b6cb52be

specs/tempest/ddt-testing.rst

@@ -1,96 +0,0 @@
-..
- This work is licensed under a Creative Commons Attribution 3.0 Unported
- License.
- http://creativecommons.org/licenses/by/3.0/legalcode
-
-===============================
-Data driven testing for Tempest
-===============================
-
-https://blueprints.launchpad.net/tempest/+spec/tempest-ddt
-
-
-Add support for data driven testing within Tempest.
-
-Problem Description
-===================
-
-Currently we see tests with for-loop that iterate through different
-data set. This can be problematic for debugging and in general
-for test separation (See [1] for some samples).
-
-
-Proposed Change
-===============
-
-Using the ddt framework [2] to extract the data out of the tests.
-DDT will dynamically create tests out of the given data set.
-The DDT framework is already heavily used by unit tests within
-the projects.
-
-Example
--------
-The test before ddt::
-
-   icmp_type_codes = [(3, 2), (3, 0), (8, 0), (0, 0), (11, None)]
-        for icmp_type, icmp_code in icmp_type_codes:
-            self._create_verify_security_group_rule(sg_id, direction,
-                                                    self.ethertype, protocol,
-                                                    icmp_type, icmp_code)
-
-Instead of iterating through a set of data the corresponding ddt code would
-look like::
-
-    @ddt.data((3, 2), (3, 0), (8, 0), (0, 0), (11, None))
-    def test_create_security_group_rule_with_icmp_type_code(self, type_codes):
-        self._create_verify_security_group_rule(sg_id, direction,
-                                                self.ethertype, protocol,
-                                                type_codes[0], type_codes[1])
-
-Performance
------------
-
-Any generated test will rerun setUp() and tearDown(). Code on class level
-should work without any change (and no rerun at all). In Tempest the resource
-setup is usually done within class methods which won't effect the performance.
-
-
-Idempotent_id and refstack
---------------------------
-
-Since refstack should handle generated tests under the same id, it should
-be fine to use the idempotent decorator to uniquely identify the test group.
-
-Implementation
-==============
-
-Assignee(s)
------------
-
-Primary assignees:
-  Marc Koderer
-
-Milestones
-----------
-
-Target Milestone for completion:
-  mitaka-3
-
-Work Items
-----------
-
-* Implement idempotent_id functionality
-* Port tests
-
-Dependencies
-============
-
-None.
-
-References
-==========
-
-1. https://review.openstack.org/#/c/223953/
-2. https://pypi.python.org/pypi/ddt
-
-.. _config_tempest.py: https://github.com/redhat-openstack/tempest/blob/master/tools/config_tempest.py