tests: Disallow use of util.subp except for where needed.

In many cases, cloud-init uses 'util.subp' to run a subprocess.
This is not really desirable in our unit tests as it makes the tests
dependent upon existance of those utilities.

The change here is to modify the base test case class (CiTestCase) to
raise exception any time subp is called.  Then, fix all callers.
For cases where subp is necessary or actually desired, we can use it
via
  a.) context hander CiTestCase.allow_subp(value)
  b.) class level self.allowed_subp = value

Both cases the value is a list of acceptable executable names that
will be called (essentially argv[0]).

Some cleanups in AltCloud were done as the code was being updated.

1 files changed, 14 insertions, 4 deletions

diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 05d5c72c..f3165da9 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -1653,6 +1653,12 @@ def _setup_test(tmp_dir, mock_get_devicelist, mock_read_sys_net,
 
 class TestGenerateFallbackConfig(CiTestCase):
 
+    def setUp(self):
+        super(TestGenerateFallbackConfig, self).setUp()
+        self.add_patch(
+            "cloudinit.util.get_cmdline", "m_get_cmdline",
+            return_value="root=/dev/sda1")
+
     @mock.patch("cloudinit.net.sys_dev_path")
     @mock.patch("cloudinit.net.read_sys_net")
     @mock.patch("cloudinit.net.get_devicelist")
@@ -1895,12 +1901,13 @@ class TestRhelSysConfigRendering(CiTestCase):
         if missing:
             raise AssertionError("Missing headers in: %s" % missing)
 
+    @mock.patch("cloudinit.net.util.get_cmdline", return_value="root=myroot")
     @mock.patch("cloudinit.net.sys_dev_path")
     @mock.patch("cloudinit.net.read_sys_net")
     @mock.patch("cloudinit.net.get_devicelist")
     def test_default_generation(self, mock_get_devicelist,
                                 mock_read_sys_net,
-                                mock_sys_dev_path):
+                                mock_sys_dev_path, m_get_cmdline):
         tmp_dir = self.tmp_dir()
         _setup_test(tmp_dir, mock_get_devicelist,
                     mock_read_sys_net, mock_sys_dev_path)
@@ -2183,12 +2190,13 @@ class TestOpenSuseSysConfigRendering(CiTestCase):
         if missing:
             raise AssertionError("Missing headers in: %s" % missing)
 
+    @mock.patch("cloudinit.net.util.get_cmdline", return_value="root=myroot")
     @mock.patch("cloudinit.net.sys_dev_path")
     @mock.patch("cloudinit.net.read_sys_net")
     @mock.patch("cloudinit.net.get_devicelist")
     def test_default_generation(self, mock_get_devicelist,
                                 mock_read_sys_net,
-                                mock_sys_dev_path):
+                                mock_sys_dev_path, m_get_cmdline):
         tmp_dir = self.tmp_dir()
         _setup_test(tmp_dir, mock_get_devicelist,
                     mock_read_sys_net, mock_sys_dev_path)
@@ -2429,12 +2437,13 @@ USERCTL=no
 
 class TestEniNetRendering(CiTestCase):
 
+    @mock.patch("cloudinit.net.util.get_cmdline", return_value="root=myroot")
     @mock.patch("cloudinit.net.sys_dev_path")
     @mock.patch("cloudinit.net.read_sys_net")
     @mock.patch("cloudinit.net.get_devicelist")
     def test_default_generation(self, mock_get_devicelist,
                                 mock_read_sys_net,
-                                mock_sys_dev_path):
+                                mock_sys_dev_path, m_get_cmdline):
         tmp_dir = self.tmp_dir()
         _setup_test(tmp_dir, mock_get_devicelist,
                     mock_read_sys_net, mock_sys_dev_path)
@@ -2482,6 +2491,7 @@ iface eth0 inet dhcp
 
 class TestNetplanNetRendering(CiTestCase):
 
+    @mock.patch("cloudinit.net.util.get_cmdline", return_value="root=myroot")
     @mock.patch("cloudinit.net.netplan._clean_default")
     @mock.patch("cloudinit.net.sys_dev_path")
     @mock.patch("cloudinit.net.read_sys_net")
@@ -2489,7 +2499,7 @@ class TestNetplanNetRendering(CiTestCase):
     def test_default_generation(self, mock_get_devicelist,
                                 mock_read_sys_net,
                                 mock_sys_dev_path,
-                                mock_clean_default):
+                                mock_clean_default, m_get_cmdline):
         tmp_dir = self.tmp_dir()
         _setup_test(tmp_dir, mock_get_devicelist,
                     mock_read_sys_net, mock_sys_dev_path)