Tox + Integration testing

This commit implements a VNF Descriptor-driven integration
test framework, which will lead to integration tests being able
to run via jenkins, and more robust testing in general.

N2VC:

- Allow the use of an event loop passed when instantiating N2VC
- Refactor the execution of the initial-config-primitive so that it can
be easily re-run, such as the case of when a proxy charm is deployed
before the VNF's VM is created.
- Refactor GetPrimitiveStatus, to return the status (queued, running,
complete, failed) of a primitive.
- Add GetPrimitiveOutput, to return the output of a completed primitive
- Fix model disconnection when executing a primitive (it was happening
in the wrong scope)
- Fix wait_for_application, which was previously unused and broken
- Add support for parameter's 'data-type' field
- Add support for better SSH key management, allowing for a proxy charm
to be deployed before the VNF, so that it's public SSH key can be
injected when the VNF's VM is created.

Integration Tests:

The integration tests are intended to exercise the expected
functionality of a VNF/charm: deploy the charm, configure it as required
(i.e., ssh credentials), and execute the VNF's
initial-config-primitives.

- test_native_charm: deploy a native charm to a juju-managed machine and
verify primitive execution works
- test_proxy_charm: deploy a proxy charm, configured to talk to a remote
machine, and verify primitive execution works
- test_metrics_native: deploy a native charm and collect a metric
- test_metrics_proxy: deploy a proxy charm and collect a metric from the
vnf
- test_no_initial-config-primitive: deploy a vnf without an
initial-config-primitive
- test_non-string_parameter: deploy a vnf with a non-string parameter in
initial-config-primitive
- test_no_parameter: deploy a vnf with a primitive with no parameters

General:
- Add a build target to tox.ini so that a .deb is built via Jenkins

TODO (in a follow-up commit):
- test multi-vdu, multi-charm
- test deploying a native charm to a manually-provisioned machine
- Update inline pydoc
- Add more integration tests
- Add global per-test timeout to catch stalled tests

Signed-off-by: Adam Israel <adam.israel@canonical.com>
Change-Id: Id322b45d65c44714e8051fc5764f8c20b76d846c
diff --git a/tests/charms/layers/native-ci/reactive/native-ci.py b/tests/charms/layers/native-ci/reactive/native-ci.py
new file mode 100644
index 0000000..17bf5f4
--- /dev/null
+++ b/tests/charms/layers/native-ci/reactive/native-ci.py
@@ -0,0 +1,44 @@
+from charmhelpers.core.hookenv import (
+    action_fail,
+    action_set,
+    action_get,
+    status_set,
+)
+from charms.reactive import (
+    clear_flag,
+    set_flag,
+    when,
+    when_not,
+)
+
+
+@when_not('native-ci.installed')
+def install_native_ci_charm():
+    set_flag('native-ci.installed')
+    status_set('active', 'Ready!')
+
+
+@when('actions.test', 'native-ci.installed')
+def test():
+    try:
+        result = True
+    except Exception as e:
+        action_fail('command failed: {}'.format(e))
+    else:
+        action_set({'output': result})
+    finally:
+        clear_flag('actions.test')
+
+
+@when('actions.testint', 'native-ci.installed')
+def testint():
+    try:
+        # Test the value is an int by performing a mathmatical operation on it.
+        intval = action_get('intval')
+        intval = intval + 1
+    except Exception as e:
+        action_fail('command failed: {}'.format(e))
+    else:
+        action_set({'output': intval})
+    finally:
+        clear_flag('actions.testint')