Relation support for multi-charm VNFs

Adds support for establishing relations between charms

Signed-off-by: Adam Israel <adam.israel@canonical.com>
Change-Id: I9a0b7725013e06635875cd824e219ab6a023efb3
diff --git a/tests/integration/test_multivdu_multicharm.py b/tests/integration/test_multivdu_multicharm.py
index e0fb9c7..b879373 100644
--- a/tests/integration/test_multivdu_multicharm.py
+++ b/tests/integration/test_multivdu_multicharm.py
@@ -144,6 +144,11 @@
                     juju:
                         charm: proxy-ci
                         proxy: true
+                        # Relation needs to map to the vdu providing or
+                        # requiring, so that we can map to the deployed app.
+                        relation:
+                        -   provides: dataVM:db
+                            requires: mgmtVM:app
                     initial-config-primitive:
                     -   seq: '1'
                         name: test