Auto-attach subscription when there is only one (#385)

Also, previous to this change, if a pool had been specified on the
convert2rhel command line and attach_subscription() was called more than
once, the subscription-manager command line would be constructed
incorrectly.  It would have "--pool" added to the front of the pool id
each time attach-subscription was called leading to something like this:
"subscription-manager attach --pool --pool POOLID".

To fix this, we now treat tool_opts.pool as read-only and do not modify
it on each call to attach_subscription().  This goes along with our
overall move to treat global singletons as read-only whenever possible.

convert2rhel/subscription.py

@@ -304,29 +304,36 @@ def attach_subscription():
     pool = ["subscription-manager", "attach"]
     if tool_opts.auto_attach:
         pool.append("--auto")
-        tool_opts.pool = "-a"
         loggerinst.info("Auto-attaching compatible subscriptions to the system ...")
     elif tool_opts.pool:
         # The subscription pool ID has been passed through a command line
         # option
         pool.extend(["--pool", tool_opts.pool])
-        tool_opts.pool = pool
         loggerinst.info("Attaching provided subscription pool ID to the system ...")
     else:
-        # Let the user choose the subscription appropriate for the conversion
-        loggerinst.info("Manually select subscription appropriate for the conversion")
         subs_list = get_avail_subs()
+
         if len(subs_list) == 0:
             loggerinst.warning("No subscription available for the conversion.")
             return False
 
-        print_avail_subs(subs_list)
-        sub_num = utils.let_user_choose_item(len(subs_list), "subscription")
-        pool.extend(["--pool", subs_list[sub_num].pool_id])
-        tool_opts.pool = pool
-        loggerinst.info("Attaching subscription with pool ID %s to the system ..." % subs_list[sub_num].pool_id)
+        elif len(subs_list) == 1:
+            sub_num = 0
+            loggerinst.info(
+                " %s is the only subscription available, it will automatically be selected for the conversion."
+                % subs_list[0].pool_id
+            )
 
+        else:
+            # Let the user choose the subscription appropriate for the conversion
+            loggerinst.info("Manually select subscription appropriate for the conversion")
+            print_avail_subs(subs_list)
+            sub_num = utils.let_user_choose_item(len(subs_list), "subscription")
+            loggerinst.info("Attaching subscription with pool ID %s to the system ..." % subs_list[sub_num].pool_id)
+
+        pool.extend(["--pool", subs_list[sub_num].pool_id])
     _, ret_code = utils.run_subprocess(pool)
+
     if ret_code != 0:
         # Unsuccessful attachment, e.g. the pool ID is incorrect or the
         # number of purchased attachments has been depleted.

convert2rhel/unit_tests/subscription_test.py

@@ -46,9 +46,20 @@ def __call__(self, *args, **kwargs):
 
 
 class TestSubscription(unittest.TestCase):
+    class GetOneSubMocked(unit_tests.MockFunction):
+        def __call__(self, *args, **kwargs):
+            Sub = namedtuple("Sub", ["pool_id", "sub_raw"])
+
+            subscription1 = Sub("samplepool", "Subscription description")
+            return [subscription1]
+
     class GetAvailSubsMocked(unit_tests.MockFunction):
         def __call__(self, *args, **kwargs):
-            return [namedtuple("Sub", ["pool_id", "sub_raw"])("samplepool", "Subscription description")]
+            Sub = namedtuple("Sub", ["pool_id", "sub_raw"])
+
+            subscription1 = Sub("samplepool", "Subscription description")
+            subscription2 = Sub("pool0", "sub desc")
+            return [subscription1, subscription2]
 
     class GetNoAvailSubsMocked(unit_tests.MockFunction):
         def __call__(self, *args, **kwargs):
@@ -67,7 +78,11 @@ def __call__(self, *args, **kwargs):
             return [namedtuple("Sub", ["pool_id", "sub_raw"])("samplepool", "Subscription description")]
 
     class LetUserChooseItemMocked(unit_tests.MockFunction):
+        def __init__(self):
+            self.called = 0
+
         def __call__(self, *args, **kwargs):
+            self.called += 1
             return 0
 
     class GetRegistrationCmdMocked(unit_tests.MockFunction):
@@ -166,6 +181,13 @@ def test_get_registration_cmd(self):
         expected = ["subscription-manager", "register", "--force", "--username=user", "--password=pass with space"]
         self.assertEqual(subscription.get_registration_cmd(), expected)
 
+    @unit_tests.mock(subscription, "get_avail_subs", GetOneSubMocked())
+    @unit_tests.mock(utils, "let_user_choose_item", LetUserChooseItemMocked())
+    @unit_tests.mock(utils, "run_subprocess", RunSubprocessMocked())
+    def test_attach_subscription_one_sub_available(self):
+        self.assertEqual(subscription.attach_subscription(), True)
+        self.assertEqual(utils.let_user_choose_item.called, 0)
+
     def test_get_registration_cmd_activation_key(self):
         tool_opts.activation_key = "activation_key"
         tool_opts.org = "org"
@@ -185,11 +207,19 @@ def test_get_registration_cmd_empty_string(self):
         self.assertEqual(subscription.get_registration_cmd(), expected)
         self.assertEqual(utils.prompt_user.called, {"Username: ": 2, "Password: ": 2})
 
+    @unit_tests.mock(subscription, "get_avail_subs", GetOneSubMocked())
+    @unit_tests.mock(utils, "let_user_choose_item", LetUserChooseItemMocked())
+    @unit_tests.mock(utils, "run_subprocess", RunSubprocessMocked())
+    def test_attach_subscription_one_sub_available(self):
+        self.assertEqual(subscription.attach_subscription(), True)
+        self.assertEqual(utils.let_user_choose_item.called, 0)
+
     @unit_tests.mock(subscription, "get_avail_subs", GetAvailSubsMocked())
     @unit_tests.mock(utils, "let_user_choose_item", LetUserChooseItemMocked())
     @unit_tests.mock(utils, "run_subprocess", RunSubprocessMocked())
-    def test_attach_subscription_available(self):
+    def test_attach_subscription_multiple_subs_available(self):
         self.assertEqual(subscription.attach_subscription(), True)
+        self.assertEqual(utils.let_user_choose_item.called, 1)
 
     @unit_tests.mock(subscription, "get_avail_subs", GetAvailSubsMocked())
     @unit_tests.mock(utils, "let_user_choose_item", LetUserChooseItemMocked())

tests/integration/tier0/check-user-response/test_user_response.py

@@ -2,7 +2,6 @@
 
 
 def test_check_user_response_user_and_password(convert2rhel):
-
     # Run c2r registration with no username and password provided
     # check for user prompt enforcing input, then continue with registration
     with convert2rhel(
@@ -52,3 +51,20 @@ def test_check_user_response_organization(convert2rhel):
         # the Ctrl+d is used to terminate the process instead
         c2r.sendcontrol("d")
     assert c2r.exitstatus != 0
+
+
+def test_auto_attach_pool_submgr(convert2rhel):
+    single_pool_id = env.str("RHSM_SINGLE_SUB_POOL")
+    with convert2rhel(
+        "-y --no-rpm-va --serverurl {} --username {} --password {} --debug".format(
+            env.str("RHSM_SERVER_URL"),
+            env.str("RHSM_SINGLE_SUB_USERNAME"),
+            env.str("RHSM_SINGLE_SUB_PASSWORD"),
+        )
+    ) as c2r:
+        c2r.expect(
+            f"{single_pool_id} is the only subscription available, it will automatically be selected for the conversion."
+        )
+        c2r.sendcontrol("d")
+
+        assert c2r.exitstatus != 0