test: fix pro integration test

Ensure Pro instances are detached before the test run and
that the test only runs on LTS releases.

As ua.UserFacingError is not properly converted to str,
manually pick its msg to provide the user a more informative
logging msg.

cloudinit/config/cc_ubuntu_advantage.py

@@ -450,7 +450,7 @@ def _auto_attach(ua_section: dict):
                 " ubuntu_advantage: enable and enable_beta"
             )
     except UserFacingError as ex:
-        msg = f"Error during `full_auto_attach`: {ex}"
+        msg = f"Error during `full_auto_attach`: {ex.msg}"
         LOG.error(msg)
         raise RuntimeError(msg) from ex
 

tests/integration_tests/modules/test_ubuntu_advantage.py

@@ -33,9 +33,19 @@
   - esm-infra
 """
 
+PRO_AUTO_ATTACH_DISABLED = """\
+#cloud-config
+ubuntu_advantage:
+  features:
+    disable_auto_attach: true
+"""
+
 PRO_DAEMON_DISABLED = """\
 #cloud-config
 # Disable UA daemon (only needed in GCE)
+ubuntu_advantage:
+  features:
+    disable_auto_attach: true
 bootcmd:
 - sudo systemctl mask ubuntu-advantage.service
 """
@@ -100,17 +110,18 @@ def get_services_status(client: IntegrationInstance) -> dict:
 
 @pytest.mark.adhoc
 @pytest.mark.ubuntu
+@pytest.mark.skipif(
+    not CLOUD_INIT_UA_TOKEN, reason="CLOUD_INIT_UA_TOKEN env var not provided"
+)
 class TestUbuntuAdvantage:
     @pytest.mark.user_data(ATTACH_FALLBACK.format(token=CLOUD_INIT_UA_TOKEN))
     def test_valid_token(self, client: IntegrationInstance):
-        assert CLOUD_INIT_UA_TOKEN, "CLOUD_INIT_UA_TOKEN env var not provided"
         log = client.read_from_file("/var/log/cloud-init.log")
         verify_clean_log(log)
         assert is_attached(client)
 
     @pytest.mark.user_data(ATTACH.format(token=CLOUD_INIT_UA_TOKEN))
     def test_idempotency(self, client: IntegrationInstance):
-        assert CLOUD_INIT_UA_TOKEN, "CLOUD_INIT_UA_TOKEN env var not provided"
         log = client.read_from_file("/var/log/cloud-init.log")
         verify_clean_log(log)
         assert is_attached(client)
@@ -144,29 +155,37 @@ def maybe_install_cloud_init(session_cloud: IntegrationCloud):
     user_data = (
         PRO_DAEMON_DISABLED
         if session_cloud.settings.PLATFORM == "gce"
-        else None
+        else PRO_AUTO_ATTACH_DISABLED
     )
 
     with session_cloud.launch(
         user_data=user_data,
         launch_kwargs=launch_kwargs,
     ) as client:
-        log = client.read_from_file("/var/log/cloud-init.log")
-        verify_clean_log(log)
+        # TODO: Re-enable this check after cloud images contain
+        # cloud-init 23.4.
+        # Explanation: We have to include something under
+        # user-data.ubuntu_advantage to skip the automatic auto-attach
+        # (driven by ua-auto-attach.service and/or ubuntu-advantage.service)
+        # while customizing the instance but in cloud-init < 23.4,
+        # user-data.ubuntu_advantage requires a token key.
+
+        # log = client.read_from_file("/var/log/cloud-init.log")
+        # verify_clean_log(log)
 
-        client.execute("sudo pro detach --assume-yes")  # Force detach
         assert not is_attached(
             client
         ), "Test precondition error. Instance is auto-attached."
 
-        LOG.info(
-            "Restore `ubuntu-advantage.service` original status for next boot"
-        )
-        assert client.execute(
-            "sudo systemctl unmask ubuntu-advantage.service"
-        ).ok
+        if session_cloud.settings.PLATFORM == "gce":
+            LOG.info(
+                "Restore `ubuntu-advantage.service` original status for next"
+                " boot"
+            )
+            assert client.execute(
+                "sudo systemctl unmask ubuntu-advantage.service"
+            ).ok
 
-        source = get_validated_source(session_cloud)
         client.install_new_cloud_init(source)
         client.destroy()
 
@@ -179,6 +198,10 @@ def maybe_install_cloud_init(session_cloud: IntegrationCloud):
 @pytest.mark.ubuntu
 class TestUbuntuAdvantagePro:
     def test_custom_services(self, session_cloud: IntegrationCloud):
+        release = ImageSpecification.from_os_image().release
+        if release not in {"bionic", "focal", "jammy"}:
+            pytest.skip(f"Cannot run on non LTS release: {release}")
+
         launch_kwargs = maybe_install_cloud_init(session_cloud)
         with session_cloud.launch(
             user_data=AUTO_ATTACH_CUSTOM_SERVICES,

tests/unittests/config/test_cc_ubuntu_advantage.py

@@ -31,7 +31,8 @@
 
 
 class FakeUserFacingError(Exception):
-    pass
+    def __init__(self, msg: str):
+        self.msg = msg
 
 
 class FakeAlreadyAttachedError(FakeUserFacingError):