Initial heat REST API tests with gabbi

Last summit we decided to add suite of gabbi tests
for REST API validation and then propose a subset of
these to tempest to be the defcore tests.

This adds the basic framework and few stack api tests
as a start.

Change-Id: I79a6fe971a97fdc4412616137ae963748cc349e5
diff --git a/api/gabbits/stacks.yaml b/api/gabbits/stacks.yaml
new file mode 100644
index 0000000..3028018
--- /dev/null
+++ b/api/gabbits/stacks.yaml
@@ -0,0 +1,47 @@
+defaults:
+  request_headers:
+    X-Auth-Token: $ENVIRON['OS_TOKEN']
+
+tests:
+- name: stack list
+  GET: /stacks
+  status: 200
+  response_headers:
+    content-type: application/json; charset=UTF-8
+
+- name: create empty stack
+  POST: /stacks
+  request_headers:
+    content-type: application/json
+  data:
+    files: {}
+    disable_rollback: true
+    parameters: {}
+    stack_name: $ENVIRON['PREFIX']-empty
+    environment: {}
+    template:
+      heat_template_version: '2016-04-08'
+
+  status: 201
+  response_headers:
+    location: //stacks/$ENVIRON['PREFIX']-empty/[a-f0-9-]+/
+
+
+- name: poll for empty CREATE_COMPLETE
+  GET: $LOCATION
+  redirects: True
+  poll:
+    count: 5
+    delay: 1.0
+  response_json_paths:
+    $.stack.stack_status: CREATE_COMPLETE
+
+- name: show empty stack
+  GET: $LAST_URL
+  redirects: True
+  status: 200
+
+- name: delete empty stack
+  DELETE: $LAST_URL
+  redirects: True
+  status: 204