Fix platform check for Debian 12

The osplatform.get_platform() check fails on Debian Bookworm
because the output determined by the /etc/os-release file has
"Debian GNU/Linux" and the get_platform() check only looks for
lowercase debian.

Signed-off-by: Billy Olsen <[email protected]>

charmhelpers/osplatform.py

@@ -9,19 +9,13 @@ def get_platform():
     will be returned (which is the name of the module).
     This string is used to decide which platform module should be imported.
     """
-    # linux_distribution is deprecated and will be removed in Python 3.7
-    # Warnings *not* disabled, as we certainly need to fix this.
-    if hasattr(platform, 'linux_distribution'):
-        tuple_platform = platform.linux_distribution()
-        current_platform = tuple_platform[0]
-    else:
-        current_platform = _get_platform_from_fs()
+    current_platform = _get_current_platform()
 
     if "Ubuntu" in current_platform:
         return "ubuntu"
     elif "CentOS" in current_platform:
         return "centos"
-    elif "debian" in current_platform:
+    elif "debian" in current_platform or "Debian" in current_platform:
         # Stock Python does not detect Ubuntu and instead returns debian.
         # Or at least it does in some build environments like Travis CI
         return "ubuntu"
@@ -36,6 +30,24 @@ def get_platform():
                            .format(current_platform))
 
 
+def _get_current_platform():
+    """Return the current platform information for the OS.
+
+    Attempts to lookup linux distribution information from the platform
+    module for releases of python < 3.7. For newer versions of python,
+    the platform is determined from the /etc/os-release file.
+    """
+    # linux_distribution is deprecated and will be removed in Python 3.7
+    # Warnings *not* disabled, as we certainly need to fix this.
+    if hasattr(platform, 'linux_distribution'):
+        tuple_platform = platform.linux_distribution()
+        current_platform = tuple_platform[0]
+    else:
+        current_platform = _get_platform_from_fs()
+
+    return current_platform
+
+
 def _get_platform_from_fs():
     """Get Platform from /etc/os-release."""
     with open(os.path.join(os.sep, 'etc', 'os-release')) as fin:
@@ -47,3 +59,4 @@ def _get_platform_from_fs():
     for k, v in content.items():
         content[k] = v.strip('"')
     return content["NAME"]
+

tests/test_osplatform.py

@@ -0,0 +1,75 @@
+#
+# Copyright (C) 2024 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+try:
+    import unittest.mock as mock
+except ImportError:
+    import mock
+
+from charmhelpers import osplatform
+
+
+class TestPlatform(unittest.TestCase):
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_ubuntu(self, _platform):
+        _platform.return_value = "Ubuntu"
+        self.assertEqual("ubuntu", osplatform.get_platform())
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_centos(self, _platform):
+        _platform.return_value = "CentOS"
+        self.assertEqual("centos", osplatform.get_platform())
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_debian(self, _platform):
+        _platform.return_value = "debian gnu/linux"
+        self.assertEqual("ubuntu", osplatform.get_platform())
+
+        _platform.return_value = "Debian GNU/Linux"
+        self.assertEqual("ubuntu", osplatform.get_platform())
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_elementary(self, _platform):
+        _platform.return_value = "elementary linux"
+        self.assertEqual("ubuntu", osplatform.get_platform())
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_pop_os(self, _platform):
+        _platform.return_value = "Pop!_OS"
+        self.assertEqual("ubuntu", osplatform.get_platform())
+
+    @mock.patch.object(osplatform, "_get_current_platform")
+    def test_get_platform_unknown(self, _platform):
+        _platform.return_value = "crazy custom flavor"
+        self.assertRaises(RuntimeError, osplatform.get_platform)
+
+    @mock.patch.object(osplatform, "_get_platform_from_fs")
+    @mock.patch.object(osplatform, "platform")
+    def test_get_current_platform_module(self, _platform, _platform_from_fs):
+        _platform.linux_distribution.return_value = ("Ubuntu", "test")
+        self.assertEqual("Ubuntu", osplatform._get_current_platform())
+        _platform_from_fs.assert_not_called()
+
+    @mock.patch.object(osplatform, "_get_platform_from_fs")
+    @mock.patch.object(osplatform, "platform")
+    def test_get_current_platform_fs(self, _platform, _platform_from_fs):
+        # make sure hasattr says False
+        del _platform.linux_distribution
+        _platform_from_fs.return_value = "foobar"
+        self.assertEqual("foobar", osplatform._get_current_platform())
+