Merge ~lamoura/update-notifier:show-only-esm-infra-alerts-on-esm-machine into update-notifier:master

[Lucas Albuquerque Medeiros de Moura]

Currently, we are showing esm-apps alerts if the user has an unauthenticated esm-apps source file and is using a LTS distro. However, we don't want to show this alert if the user is using a ESM distro, since esm-apps will not do much in that situation. We are updating that alert to show only
if the user is not using a ESM distro.

To test that change, we have used the following script:
--------------------------------------------------------

#!/bin/sh
set -x

series=xenial
name=$series-dev

function generate_motd_message() {
    message=$1
    echo "-----------------------------------------------------------"
    echo $message
    lxc exec $name -- /usr/lib/update-notifier/update-motd-updates-available --force
    lxc exec $name -- update-motd
    echo "-----------------------------------------------------------"
}

function setup_update_notifier_from_ppa() {
    lxc exec $name -- add-apt-repository ppa:lamoura/update-notifier-test-ppa -y
    lxc exec $name -- apt update
    lxc exec $name -- sh -c "apt install update-notifier -yq > /dev/null"
}

function setup_update_notifier_from_proposed() {
    lxc exec $name -- sh -c "cat <<EOF >/etc/apt/sources.list.d/ubuntu-$series-proposed.list
    deb http://archive.ubuntu.com/ubuntu/ $series-proposed restricted main multiverse universe"
    lxc exec $name -- apt update
    lxc exec $name -- sh -c "apt install update-notifier -yq > /dev/null"
}

function install_ua() {

config_file="# Ubuntu-Advantage client config file.
contract_url: 'https://contracts.canonical.com'
security_url: 'https://ubuntu.com/security'
data_dir: /var/lib/ubuntu-advantage
log_level: debug
log_file: /var/log/ubuntu-advantage.log
features:
  allow_beta: true"

    lxc exec $name -- add-apt-repository ppa:ua-client/daily -y
    lxc exec $name -- sudo apt-get update
    lxc exec $name -- mkdir /etc/ubuntu-advantage/
    lxc exec $name -- touch /etc/ubuntu-advantage/uaclient.conf
    lxc exec $name -- sh -c "echo '$config_file' >> /etc/ubuntu-advantage/uaclient.conf"
    lxc exec $name -- sh -c "yes N | apt-get install ubuntu-advantage-tools -y"
    lxc exec $name -- ua version
    lxc exec $name -- sudo apt-get update
}

function install_update_motd() {
    lxc exec $name -- apt install update-motd -yq
}

lxc delete --force $name
lxc launch ubuntu-daily:$series $name
sleep 10

setup_update_notifier_from_proposed
install_update_motd
install_ua
generate_motd_message "xenial-esm"
setup_update_notifier_from_ppa
generate_motd_message "xenial-esm"

set +x
------------------------------

Additionally, the xenial version of this package can already be found on the following ppa:
https://launchpad.net/~lamoura/+archive/ubuntu/update-notifier-test-ppa/

[Chad Smith (chad.smith)]

Lucas , thanks for this. A note about a change Lech requested today on https://github.com/canonical/ubuntu-advantage-client/issues/1584 would ask that we also adapt the following text:

Learn more about enabling UA Infra: ESM service at https://ubuntu.com/esm

TO

Learn more about enabling UA Infra: ESM service for Ubuntu 16.04 at https://ubuntu.com/16-04

on active ESM releases for Infra service.

Note that when Bionic or Fcal goes into ESM we'll need something like:

Learn more about enabling UA Infra: ESM service for Ubuntu 18.04 at https://ubuntu.com/18-04

[Brian Murray (brian-murray)]

These changes look good to me but I imagine you'll want to SRU them. Do you have SRU bugs prepared? If you do could please add and updated changelog entry too?

review: Needs Information

[Lucas Albuquerque Medeiros de Moura (lamoura)]

Hi Brian, thanks for the review. About the SRU bug, yes we have one already for it:
https://bugs.launchpad.net/ubuntu/+source/update-notifier/+bug/1926990

I have also added the code to retry on calling lsb_release and I have added a new entry on changelog too

[Brian Murray (brian-murray)]

I think instead of retrying a call to lsb_release a number of times it'd be better to use a different mechanism to determine the codename i.e. by reading it out of /etc/os-release. Additionally, if there is such a fallback mechanism in place it should also exist for get_distro_version(). Thanks!

review: Needs Fixing

[Lucas Albuquerque Medeiros de Moura (lamoura)]

Thank you for the review Brian, I have updated the code to source both distro name and version from
/etc/os-release

[Lucas Albuquerque Medeiros de Moura (lamoura)]

Brian, also we could have named exceptions here, but I don't know if that is an overkill for the script

[Brian Murray (brian-murray)]

I've one inline comment.

[Lucas Albuquerque Medeiros de Moura (lamoura)]

Good catch Brian, I have updated the code

[Chad Smith (chad.smith)]

integration Test runs:
#### xenial should prefer infra messages
 # esm-infra and esm-apps disabled
UA Infra: Extended Security Maintenance (ESM) is not enabled.

25 updates can be applied immediately.
1 of these updates is a standard security update.
To see these additional updates run: apt list --upgradable

Enable UA Infra: ESM to receive additional future security updates.
See https://ubuntu.com/esm or run: sudo ua status

# esm-infra enabled
UA Infra: Extended Security Maintenance (ESM) is enabled.

25 updates can be applied immediately.
1 of these updates is a standard security update.
To see these additional updates run: apt list --upgradable

# esm-infra and esm-apps enabled
UA Infra: Extended Security Maintenance (ESM) is enabled.

25 updates can be applied immediately.
1 of these updates is a UA Apps: ESM security update.
1 of these updates is a standard security update.
To see these additional updates run: apt list --upgradable

# esm-apps enabled
UA Infra: Extended Security Maintenance (ESM) is not enabled.

24 updates can be applied immediately.
1 of these updates is a UA Apps: ESM security update.
1 of these updates is a standard security update.
To see these additional updates run: apt list --upgradable

Enable UA Infra: ESM to receive additional future security updates.
See https://ubuntu.com/esm or run: sudo ua status

# Bionic, I'm surprised we don't also have a message about "UA Apps: Extended Security Maintenance (ESM) is enabled." on LTS releases that are not in active ESM (bionic++). I was under the impression that we needed it there when ESM-Apps gets released. This can be handled later, but something we should check on for next Bionic SRU

[Lucas Albuquerque Medeiros de Moura (lamoura)]

Hi Chad, thank you for the review.

I have opened a PR to handle the esm-apps header situation:
https://code.launchpad.net/~lamoura/update-notifier/+git/update-notifier/+merge/402587

And for the version id case, I don't know if we should handle it. This is corner case, and I think we should fail earlier on that situation, because as you said, we will not have the distro info as well. But, the corner case of the corner case is if we have os-release, but not VERSION_ID on it. Maybe, in that situation it is worth making that check

diff --git a/data/apt_check.py b/data/apt_check.py
index 2f2bb3d..3b9998c 100755
--- a/data/apt_check.py
+++ b/data/apt_check.py
@@ -8,14 +8,45 @@ import apt_pkg
 import os
 import sys
 from optparse import OptionParser
+import re
 import gettext
-import subprocess
 import distro_info
 
+
 SYNAPTIC_PINFILE = "/var/lib/synaptic/preferences"
-DISTRO = subprocess.check_output(
-    ["lsb_release", "-c", "-s"],
-    universal_newlines=True).strip()
+OS_RELEASE_PATH = "/etc/os-release"
+
+
+def _get_info_from_os_release(key):
+    " get info directly from os-release file "
+    if os.path.exists(OS_RELEASE_PATH):
+        with open(OS_RELEASE_PATH) as f:
+            search_res = re.search(
+                r"{}=(?P<name>.*)".format(key),
+                f.read()
+            )
+            if search_res:
+                return search_res.group("name")
+            else:
+                raise Exception(
+                    "Could not find {} in {}".format(
+                        key, OS_RELEASE_PATH
+                    )
+                )
+    else:
+        raise Exception(
+            "File {} was not found on the system".format(
+                OS_RELEASE_PATH
+            )
+        )
+
+
+def get_distro():
+    " get distro name "
+    return _get_info_from_os_release(key="UBUNTU_CODENAME")
+
+
+DISTRO = get_distro()
 
 ESM_INFRA_ORIGIN = "UbuntuESM"
 ESM_APPS_ORIGIN = "UbuntuESMApps"
@@ -31,6 +62,11 @@ def _handleException(type, value, tb):
     sys.exit(-1)
 
 
+def get_distro_version():
+    " get distro version "
+    return _get_info_from_os_release(key="VERSION_ID").replace('"', "")
+
+
 def clean(cache, depcache):
     " unmark (clean) all changes from the given depcache "
     # mvo: looping is too inefficient with the new auto-mark code
@@ -112,7 +148,7 @@ def _output_esm_package_count(outstream, service_type, esm_pkg_count):
         outstream.write("\n")
         outstream.write(gettext.dngettext("update-notifier",
                                           "%d of these updates "
-                                          "is an UA %s: ESM "
+                                          "is a UA %s: ESM "
                                           "security update.",
                                           "%d of these updates "
                                           "are UA %s: ESM "
@@ -122,27 +158,37 @@ def _output_esm_package_count(outstream, service_type, esm_pkg_count):
 
 
 def _output_esm_package_alert(
-    outstream, service_type, disabled_pkg_count
+    outstream, service_type, disabled_pkg_count, is_esm=False
 ):
     " output the number of upgradable packages if esm service was enabled "
     outstream.write("\n")
     if disabled_pkg_count > 0:
         outstream.write("\n")
+
+        if is_esm:
+            distro_version = get_distro_version()
+            esm_info_url = "https://ubuntu.com/{}".format(
+                distro_version.replace(".", "-")
+            )
+            learn_msg_suffix = "for Ubuntu {} at\n{}".format(
+                distro_version, esm_info_url)
+        else:
+            learn_msg_suffix = "at https://ubuntu.com/esm"
+
         outstream.write(gettext.dngettext("update-notifier",
                                           "%i additional security "
                                           "update can be applied "
                                           "with UA %s: ESM\nLearn "
                                           "more about enabling UA "
-                                          "%s: ESM service at "
-                                          "https://ubuntu.com/esm",
+                                          "%s: ESM service %s",
                                           "%i additional security "
                                           "updates can be applied "
                                           "with UA %s: ESM\nLearn "
                                           "more about enabling UA "
-                                          "%s: ESM service at "
-                                          "https://ubuntu.com/esm",
+                                          "%s: ESM service %s",
                                           disabled_pkg_count) %
-                        (disabled_pkg_count, service_type, service_type))
+                        (disabled_pkg_count, service_type, service_type,
+                         learn_msg_suffix))
     else:
         outstream.write("\n")
         outstream.write(gettext.dgettext("update-notifier",
@@ -179,15 +225,14 @@ def write_human_readable_summary(outstream, upgrades, security_updates,
                                              "UA Infra: Extended "
                                              "Security Maintenance (ESM) is "
                                              "not enabled."))
-        if upgrades > 0:
-            outstream.write("\n\n")
-    if upgrades > 0:
-        outstream.write(
-            gettext.dngettext("update-notifier",
-                              "%i update can be applied immediately.",
-                              "%i updates can be applied immediately.",
-                              upgrades) % upgrades
-        )
+        outstream.write("\n\n")
+
+    outstream.write(
+        gettext.dngettext("update-notifier",
+                          "%i update can be applied immediately.",
+                          "%i updates can be applied immediately.",
+                          upgrades) % upgrades
+    )
 
     _output_esm_package_count(
         outstream, service_type="Infra", esm_pkg_count=esm_infra_updates)
@@ -210,7 +255,14 @@ def write_human_readable_summary(outstream, upgrades, security_updates,
                                          "To see these additional updates "
                                          "run: apt list --upgradable"))
 
-    if have_esm_apps is not None and not have_esm_apps and lts_distro:
+    if all(
+        [
+            have_esm_apps is not None,
+            not have_esm_apps,
+            lts_distro,
+            not esm_distro
+        ]
+    ):
         _output_esm_package_alert(
             outstream, service_type="Apps",
             disabled_pkg_count=disabled_esm_apps_updates)
@@ -218,7 +270,9 @@ def write_human_readable_summary(outstream, upgrades, security_updates,
     if have_esm_infra is not None and not have_esm_infra and esm_distro:
         _output_esm_package_alert(
             outstream, service_type="Infra",
-            disabled_pkg_count=disabled_esm_infra_updates)
+            disabled_pkg_count=disabled_esm_infra_updates,
+            is_esm=True
+        )
 
     outstream.write("\n")
 
diff --git a/debian/changelog b/debian/changelog
index afd3937..af2f8c3 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,14 @@
+update-notifier (3.192.43) impish; urgency=medium
+
+  * data/apt_check.py
+    - Only show esm-apps alerts on lts and non-esm distros (LP: #1926990)
+    - Update esm-infra alert for distros on ESM mode
+    - Show message with number of upgradable packages even if that
+      number is zero (LP: #1926819)
+    - Get distro name and version directly from /etc/os-release
+
+ -- Lucas Moura <[e-mail]>  Fri, 07 May 2021 10:47:49 -0300
+
 update-notifier (3.192.42) impish; urgency=medium
 
   [ Dan Bungert ]
diff --git a/tests/test_motd.py b/tests/test_motd.py
index 335adce..26d4d4d 100755
--- a/tests/test_motd.py
+++ b/tests/test_motd.py
@@ -18,10 +18,11 @@ def get_message(*args, **kwds):
 class TestMotd(unittest.TestCase):
     """ Validate /etc/motd text """
 
+    @mock.patch("apt_check.get_distro_version", return_value="16.04")
     @mock.patch("apt_check.is_lts_distro", return_value=True)
     @mock.patch("apt_check.is_esm_distro", return_value=True)
     def test_esm_infra_disabled_upto_date_esm_avail(
-        self, _m_esm_distro, _m_is_lts
+        self, _m_esm_distro, _m_is_lts, _m_distro_version
     ):
         self.assertEqual(
             get_message(upgrades=0, security_updates=0,
@@ -33,17 +34,18 @@ class TestMotd(unittest.TestCase):
                 """\
                 UA Infra: Extended Security Maintenance (ESM) is not enabled.
 
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
+                0 updates can be applied immediately.
 
                 1 additional security update can be applied with UA Infra: ESM
-                Learn more about enabling UA Infra: ESM service at https://ubuntu.com/esm
+                Learn more about enabling UA Infra: ESM service for Ubuntu 16.04 at
+                https://ubuntu.com/16-04
                 """))
 
+    @mock.patch("apt_check.get_distro_version", return_value="18.04")
     @mock.patch("apt_check.is_lts_distro", return_value=True)
     @mock.patch("apt_check.is_esm_distro", return_value=True)
     def test_esm_infra_disabled_security_esm_avail(
-        self, _m_esm_distro, _m_is_lts
+        self, _m_esm_distro, _m_is_lts, _m_distro_version
     ):
         self.assertEqual(
             get_message(upgrades=15, security_updates=1,
@@ -59,11 +61,9 @@ class TestMotd(unittest.TestCase):
                 1 of these updates is a standard security update.
                 To see these additional updates run: apt list --upgradable
 
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
-
                 23 additional security updates can be applied with UA Infra: ESM
-                Learn more about enabling UA Infra: ESM service at https://ubuntu.com/esm
+                Learn more about enabling UA Infra: ESM service for Ubuntu 18.04 at
+                https://ubuntu.com/18-04
                 """))
 
     @mock.patch("apt_check.is_lts_distro", return_value=True)
@@ -85,9 +85,6 @@ class TestMotd(unittest.TestCase):
                 7 of these updates are standard security updates.
                 To see these additional updates run: apt list --upgradable
 
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
-
                 Enable UA Infra: ESM to receive additional future security updates.
                 See https://ubuntu.com/esm or run: sudo ua status
                 """))
@@ -110,9 +107,6 @@ class TestMotd(unittest.TestCase):
                 15 updates can be applied immediately.
                 To see these additional updates run: apt list --upgradable
 
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
-
                 Enable UA Infra: ESM to receive additional future security updates.
                 See https://ubuntu.com/esm or run: sudo ua status
                 """))
@@ -132,8 +126,7 @@ class TestMotd(unittest.TestCase):
                 """\
                 UA Infra: Extended Security Maintenance (ESM) is not enabled.
 
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
+                0 updates can be applied immediately.
 
                 Enable UA Infra: ESM to receive additional future security updates.
                 See https://ubuntu.com/esm or run: sudo ua status
@@ -157,9 +150,6 @@ class TestMotd(unittest.TestCase):
                 35 updates can be applied immediately.
                 13 of these updates are UA Infra: ESM security updates.
                 To see these additional updates run: apt list --upgradable
-
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
                 """))
 
     @mock.patch("apt_check.is_lts_distro", return_value=True)
@@ -181,9 +171,6 @@ class TestMotd(unittest.TestCase):
                 13 of these updates are UA Infra: ESM security updates.
                 7 of these updates are standard security updates.
                 To see these additional updates run: apt list --upgradable
-
-                Enable UA Apps: ESM to receive additional future security updates.
-                See https://ubuntu.com/esm or run: sudo ua status
                 """))
 
     @mock.patch("apt_check.is_lts_distro", return_value=True)
@@ -201,8 +188,7 @@ class TestMotd(unittest.TestCase):
                 """\
                 UA Infra: Extended Security Maintenance (ESM) is enabled.
 
-                10 additional security updates can be applied with UA Apps: ESM
-                Learn more about enabling UA Apps: ESM service at https://ubuntu.com/esm
+                0 updates can be applied immediately.
                 """))
 
     @mock.patch("apt_check.is_lts_distro", return_value=True)
@@ -250,10 +236,11 @@ class TestMotd(unittest.TestCase):
                 See https://ubuntu.com/esm or run: sudo ua status
                 """).lstrip())
 
+    @mock.patch("apt_check.get_distro_version", return_value="16.04")
     @mock.patch("apt_check.is_lts_distro", return_value=True)
     @mock.patch("apt_check.is_esm_distro", return_value=True)
     def test_esm_infra_disabled_wih_pkgs_and_esm_apps_enabled(
-        self, _m_esm_distro, _m_is_lts
+        self, _m_esm_distro, _m_is_lts, _m_distro_version
     ):
         self.assertEqual(
             get_message(upgrades=30, security_updates=15,
@@ -266,12 +253,13 @@ class TestMotd(unittest.TestCase):
                 UA Infra: Extended Security Maintenance (ESM) is not enabled.
 
                 30 updates can be applied immediately.
-                1 of these updates is an UA Apps: ESM security update.
+                1 of these updates is a UA Apps: ESM security update.
                 15 of these updates are standard security updates.
                 To see these additional updates run: apt list --upgradable
 
                 40 additional security updates can be applied with UA Infra: ESM
-                Learn more about enabling UA Infra: ESM service at https://ubuntu.com/esm
+                Learn more about enabling UA Infra: ESM service for Ubuntu 16.04 at
+                https://ubuntu.com/16-04
                 """).lstrip())
 
     @mock.patch("apt_check.is_lts_distro", return_value=True)
@@ -293,9 +281,6 @@ class TestMotd(unittest.TestCase):
                 18 of these updates are standard security updates.
                 To see these additional updates run: apt list --upgradable
 
-                40 additional security updates can be applied with UA Apps: ESM
-                Learn more about enabling UA Apps: ESM service at https://ubuntu.com/esm
-
                 Enable UA Infra: ESM to receive additional future security updates.
                 See https://ubuntu.com/esm or run: sudo ua status
                 """))
@@ -398,6 +383,217 @@ class TestMotd(unittest.TestCase):
                 Learn more about enabling UA Apps: ESM service at https://ubuntu.com/esm
                 """))
 
+    @mock.patch("apt_check.is_lts_distro", return_value=False)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_no_upgrades_non_lts_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=0, security_updates=0,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                0 updates can be applied immediately.
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=False)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_one_upgrade_non_lts_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=1, security_updates=0,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                1 update can be applied immediately.
+                To see these additional updates run: apt list --upgradable
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=False)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_one_security_upgrade_non_lts_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=1, security_updates=1,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                1 update can be applied immediately.
+                1 of these updates is a standard security update.
+                To see these additional updates run: apt list --upgradable
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=True)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_no_upgrades_lts_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=0, security_updates=0,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                0 updates can be applied immediately.
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=True)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_no_upgrades_lts_distro_with_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=0, security_updates=0,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=False, have_esm_apps=False,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                0 updates can be applied immediately.
+
+                Enable UA Apps: ESM to receive additional future security updates.
+                See https://ubuntu.com/esm or run: sudo ua status
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=True)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_one_upgrade_esm_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=1, security_updates=0,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                1 update can be applied immediately.
+                To see these additional updates run: apt list --upgradable
+                """))
+
+    @mock.patch("apt_check.is_lts_distro", return_value=True)
+    @mock.patch("apt_check.is_esm_distro", return_value=False)
+    def test_message_one_security_upgrade_esm_distro_without_esm_sources(
+        self, _m_is_esm, _m_is_lts
+    ):
+        self.assertEqual(
+            get_message(upgrades=1, security_updates=1,
+                        esm_infra_updates=0, esm_apps_updates=0,
+                        have_esm_infra=None, have_esm_apps=None,
+                        disabled_esm_infra_updates=0,
+                        disabled_esm_apps_updates=0),
+            textwrap.dedent(
+                """\
+                1 update can be applied immediately.
+                1 of these updates is a standard security update.
+                To see these additional updates run: apt list --upgradable
+                """))
+
+
+class TestGetDistro(unittest.TestCase):
+    @mock.patch("os.path.exists", return_value=True)
+    def test_get_distro_happy_path(self, _m_path):
+        read_data = (
+            "UBUNTU_CODENAME=test\n"
+            "NAME=Ubuntu\n"
+            "VERSION=version\n"
+            "ID=ubuntu\n"
+            "ID_LIKE=debian\n"
+            "PRETTY_NAME=Ubuntu XX.XX\n"
+            "VERSION_ID=XX.XX\n"
+        )
+
+        expected_value = "test"
+        with mock.patch(
+            "builtins.open",
+            mock.mock_open(read_data=read_data)
+        ) as m_open:
+            assert apt_check.get_distro() == expected_value
+            assert 1 == _m_path.call_count
+            assert [
+                mock.call(apt_check.OS_RELEASE_PATH)
+            ] == m_open.call_args_list
+
+    @mock.patch("os.path.exists", return_value=True)
+    def test_get_distro_no_ubuntu_codename(self, _m_path):
+        read_data = (
+            "NAME=Ubuntu\n"
+            "VERSION=version\n"
+            "ID=ubuntu\n"
+            "ID_LIKE=debian\n"
+            "PRETTY_NAME=Ubuntu XX.XX\n"
+            "VERSION_ID=XX.XX\n"
+        )
+        expected_msg = (
+            "Could not find UBUNTU_CODENAME in "
+        ) + apt_check.OS_RELEASE_PATH
+
+        with mock.patch(
+            "builtins.open",
+            mock.mock_open(read_data=read_data)
+        ) as m_open:
+            with self.assertRaises(Exception) as context:
+                apt_check.get_distro()
+
+            assert expected_msg == str(context.exception)
+
+            assert 1 == _m_path.call_count
+            assert [
+                mock.call(apt_check.OS_RELEASE_PATH)
+            ] == m_open.call_args_list
+
+    @mock.patch("os.path.exists", return_value=False)
+    def test_get_distro_no_os_release(self, _m_path):
+        expected_msg = "File {} was not found on the system".format(
+            apt_check.OS_RELEASE_PATH
+        )
+
+        with self.assertRaises(Exception) as context:
+            apt_check.get_distro()
+
+        assert expected_msg == str(context.exception)
+        assert 1 == _m_path.call_count
+
+
+class TestDistroVersion(unittest.TestCase):
+    @mock.patch("os.path.exists", return_value=True)
+    def test_get_distro_version_happy_path(self, _m_path):
+        read_data = (
+            "UBUNTU_CODENAME=test\n"
+            "NAME=Ubuntu\n"
+            "VERSION=version\n"
+            "ID=ubuntu\n"
+            "ID_LIKE=debian\n"
+            "PRETTY_NAME=Ubuntu XX.XX\n"
+            'VERSION_ID="XX.XX"\n'
+        )
+
+        expected_value = "XX.XX"
+        with mock.patch(
+            "builtins.open",
+            mock.mock_open(read_data=read_data)
+        ) as m_open:
+            assert apt_check.get_distro_version() == expected_value
+            assert 1 == _m_path.call_count
+            assert [
+                mock.call(apt_check.OS_RELEASE_PATH)
+            ] == m_open.call_args_list
+
 
 if __name__ == "__main__":
     import logging