Improve detection of snappy to include os-release and kernel cmdline.

Recent core snap images (edge channel revision 1886) do not contain the
previously known files used to detect that a system is ubuntu core.

The changes here are to look in 2 additional locations to determine
if a system is snappy.

LP: #1689944

2 files changed, 72 insertions, 4 deletions

diff --git a/tests/unittests/helpers.py b/tests/unittests/helpers.py
index a711404c..d24f817d 100644
--- a/tests/unittests/helpers.py
+++ b/tests/unittests/helpers.py
@@ -106,7 +106,7 @@ class CiTestCase(TestCase):
         return os.path.normpath(os.path.abspath(os.path.join(dir, path)))
 
 
-class ResourceUsingTestCase(TestCase):
+class ResourceUsingTestCase(CiTestCase):
     def setUp(self):
         super(ResourceUsingTestCase, self).setUp()
         self.resource_path = None
@@ -229,8 +229,7 @@ class FilesystemMockingTestCase(ResourceUsingTestCase):
 
     def reRoot(self, root=None):
         if root is None:
-            root = tempfile.mkdtemp()
-            self.addCleanup(shutil.rmtree, root)
+            root = self.tmp_dir()
         self.patchUtils(root)
         self.patchOS(root)
         return root
@@ -256,7 +255,7 @@ def populate_dir(path, files):
         os.makedirs(path)
     ret = []
     for (name, content) in files.items():
-        p = os.path.join(path, name)
+        p = os.path.sep.join([path, name])
         util.ensure_dir(os.path.dirname(p))
         with open(p, "wb") as fp:
             if isinstance(content, six.binary_type):
diff --git a/tests/unittests/test_util.py b/tests/unittests/test_util.py
index 189caca8..490760d1 100644
--- a/tests/unittests/test_util.py
+++ b/tests/unittests/test_util.py
@@ -712,4 +712,73 @@ class TestProcessExecutionError(helpers.TestCase):
             )).format(description=self.empty_description,
                       empty_attr=self.empty_attr))
 
+
+class TestSystemIsSnappy(helpers.FilesystemMockingTestCase):
+    def test_id_in_os_release_quoted(self):
+        """os-release containing ID="ubuntu-core" is snappy."""
+        orcontent = '\n'.join(['ID="ubuntu-core"', ''])
+        root_d = self.tmp_dir()
+        helpers.populate_dir(root_d, {'etc/os-release': orcontent})
+        self.reRoot(root_d)
+        self.assertTrue(util.system_is_snappy())
+
+    def test_id_in_os_release(self):
+        """os-release containing ID=ubuntu-core is snappy."""
+        orcontent = '\n'.join(['ID=ubuntu-core', ''])
+        root_d = self.tmp_dir()
+        helpers.populate_dir(root_d, {'etc/os-release': orcontent})
+        self.reRoot(root_d)
+        self.assertTrue(util.system_is_snappy())
+
+    @mock.patch('cloudinit.util.get_cmdline')
+    def test_bad_content_in_os_release_no_effect(self, m_cmdline):
+        """malformed os-release should not raise exception."""
+        m_cmdline.return_value = 'root=/dev/sda'
+        orcontent = '\n'.join(['IDubuntu-core', ''])
+        root_d = self.tmp_dir()
+        helpers.populate_dir(root_d, {'etc/os-release': orcontent})
+        self.reRoot()
+        self.assertFalse(util.system_is_snappy())
+
+    @mock.patch('cloudinit.util.get_cmdline')
+    def test_snap_core_in_cmdline_is_snappy(self, m_cmdline):
+        """The string snap_core= in kernel cmdline indicates snappy."""
+        cmdline = (
+            "BOOT_IMAGE=(loop)/kernel.img root=LABEL=writable "
+            "snap_core=core_x1.snap snap_kernel=pc-kernel_x1.snap ro "
+            "net.ifnames=0 init=/lib/systemd/systemd console=tty1 "
+            "console=ttyS0 panic=-1")
+        m_cmdline.return_value = cmdline
+        self.assertTrue(util.system_is_snappy())
+        self.assertTrue(m_cmdline.call_count > 0)
+
+    @mock.patch('cloudinit.util.get_cmdline')
+    def test_nothing_found_is_not_snappy(self, m_cmdline):
+        """If no positive identification, then not snappy."""
+        m_cmdline.return_value = 'root=/dev/sda'
+        self.reRoot()
+        self.assertFalse(util.system_is_snappy())
+        self.assertTrue(m_cmdline.call_count > 0)
+
+    @mock.patch('cloudinit.util.get_cmdline')
+    def test_channel_ini_with_snappy_is_snappy(self, m_cmdline):
+        """A Channel.ini file with 'ubuntu-core' indicates snappy."""
+        m_cmdline.return_value = 'root=/dev/sda'
+        root_d = self.tmp_dir()
+        content = '\n'.join(["[Foo]", "source = 'ubuntu-core'", ""])
+        helpers.populate_dir(
+            root_d, {'etc/system-image/channel.ini': content})
+        self.reRoot(root_d)
+        self.assertTrue(util.system_is_snappy())
+
+    @mock.patch('cloudinit.util.get_cmdline')
+    def test_system_image_config_dir_is_snappy(self, m_cmdline):
+        """Existence of /etc/system-image/config.d indicates snappy."""
+        m_cmdline.return_value = 'root=/dev/sda'
+        root_d = self.tmp_dir()
+        helpers.populate_dir(
+            root_d, {'etc/system-image/config.d/my.file': "_unused"})
+        self.reRoot(root_d)
+        self.assertTrue(util.system_is_snappy())
+
 # vi: ts=4 expandtab