integration_tests: introduce lxd_use_exec mark (#802)

pycloudlib has modified the way LXD executes tests
(https://github.com/canonical/pycloudlib/pull/114): it will always use
SSH to access them by default, instead of using `lxc exec`.  This
behaviour is transparent for them majority of cloud-init's integration
tests, but some currently depend on using `lxc exec` to access instances
with (intentionally) broken networking: obviously these are not
accessible via SSH.

pycloudlib retains support for switching an instance to use `lxc exec`.
This commit introduces the `lxd_use_exec` mark, which tests can use to
indicate to the integration testing framework that they should be so
switched, and applies it to all applicable tests.

3 files changed, 13 insertions, 0 deletions

diff --git a/tests/integration_tests/bugs/test_gh668.py b/tests/integration_tests/bugs/test_gh668.py
index 72fe0afc..ce57052e 100644
--- a/tests/integration_tests/bugs/test_gh668.py
+++ b/tests/integration_tests/bugs/test_gh668.py
@@ -37,6 +37,7 @@ EXPECTED_ROUTE = "{} via {}".format(DESTINATION_IP, GATEWAY_IP)
     "user.network-config": NETWORK_CONFIG,
     "volatile.eth0.hwaddr": MAC_ADDRESS,
 })
+@pytest.mark.lxd_use_exec
 def test_static_route_to_host(client: IntegrationInstance):
     route = client.execute("ip route | grep {}".format(DESTINATION_IP))
     assert route.startswith(EXPECTED_ROUTE)
diff --git a/tests/integration_tests/bugs/test_lp1898997.py b/tests/integration_tests/bugs/test_lp1898997.py
index 90dc17da..bde93d06 100644
--- a/tests/integration_tests/bugs/test_lp1898997.py
+++ b/tests/integration_tests/bugs/test_lp1898997.py
@@ -39,6 +39,7 @@ version: 2
     "volatile.eth0.hwaddr": MAC_ADDRESS,
 })
 @pytest.mark.lxd_vm
+@pytest.mark.lxd_use_exec
 @pytest.mark.not_bionic
 @pytest.mark.not_xenial
 @pytest.mark.sru_2020_11
diff --git a/tests/integration_tests/conftest.py b/tests/integration_tests/conftest.py
index 3933d647..61ad8a71 100644
--- a/tests/integration_tests/conftest.py
+++ b/tests/integration_tests/conftest.py
@@ -200,6 +200,9 @@ def _client(request, fixture_utils, session_cloud: IntegrationCloud):
     user_data = getter('user_data')
     name = getter('instance_name')
     lxd_config_dict = getter('lxd_config_dict')
+    lxd_use_exec = fixture_utils.closest_marker_args_or(
+        request, 'lxd_use_exec', None
+    )
 
     launch_kwargs = {}
     if name is not None:
@@ -208,10 +211,18 @@ def _client(request, fixture_utils, session_cloud: IntegrationCloud):
         if not isinstance(session_cloud, _LxdIntegrationCloud):
             pytest.skip("lxd_config_dict requires LXD")
         launch_kwargs["config_dict"] = lxd_config_dict
+    if lxd_use_exec is not None:
+        if not isinstance(session_cloud, _LxdIntegrationCloud):
+            pytest.skip("lxd_use_exec requires LXD")
+        launch_kwargs["execute_via_ssh"] = False
 
     with session_cloud.launch(
         user_data=user_data, launch_kwargs=launch_kwargs
     ) as instance:
+        if lxd_use_exec is not None:
+            # Existing instances are not affected by the launch kwargs, so
+            # ensure it here; we still need the launch kwarg so waiting works
+            instance.execute_via_ssh = False
         previous_failures = request.session.testsfailed
         yield instance
         test_failed = request.session.testsfailed - previous_failures > 0