expose /slice/<slice_id>/ endpoint to redirect to a slice's url (#633)

* expose /slice/<slice_id>/ endpoint to redirect to a slice's url

* remove residual print statement

* add unit test for caravel/slices/id endpoint

caravel/views.py

@@ -953,6 +953,19 @@ class Caravel(BaseView):
             json.dumps({'count': count}),
             mimetype="application/json")
 
+    @has_access
+    @expose("/slice/<slice_id>/")
+    def slice(self, slice_id):
+        """Redirects a request for a slice id to its corresponding URL"""
+        session = db.session()
+        qry = session.query(models.Slice).filter_by(id=int(slice_id))
+        slc = qry.first()
+        if slc:
+            return redirect(slc.slice_url)
+        else:
+            flash("The specified slice could not be found", "danger")
+            return redirect('/slicemodelview/list/')
+
     @has_access
     @expose("/dashboard/<dashboard_id>/")
     def dashboard(self, dashboard_id):

tests/core_tests.py

@@ -140,13 +140,14 @@ class CoreTests(CaravelTestCase):
         assert 'Energy' in resp.data.decode('utf-8')
 
     def test_slices(self):
-        # Testing by running all the examples
+        # Testing by hitting the two supported end points for all slices
         self.login(username='admin')
         Slc = models.Slice
         urls = []
         for slc in db.session.query(Slc).all():
             urls += [
-                (slc.slice_name, 'slice_url',  slc.slice_url),
+                (slc.slice_name, 'slice_url', slc.slice_url),
+                (slc.slice_name, 'slice_id_endpoint', '/caravel/slices/{}'.format(slc.id)),
                 (slc.slice_name, 'json_endpoint', slc.viz.json_endpoint),
                 (slc.slice_name, 'csv_endpoint', slc.viz.csv_endpoint),
             ]