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, 9 insertions, 3 deletions

diff --git a/tests/unittests/test_handler/test_schema.py b/tests/unittests/test_handler/test_schema.py
index fb266faf..1bad07f6 100644
--- a/tests/unittests/test_handler/test_schema.py
+++ b/tests/unittests/test_handler/test_schema.py
@@ -4,7 +4,7 @@ from cloudinit.config.schema import (
     CLOUD_CONFIG_HEADER, SchemaValidationError, annotated_cloudconfig_file,
     get_schema_doc, get_schema, validate_cloudconfig_file,
     validate_cloudconfig_schema, main)
-from cloudinit.util import subp, write_file
+from cloudinit.util import write_file
 
 from cloudinit.tests.helpers import CiTestCase, mock, skipUnlessJsonSchema
 
@@ -406,8 +406,14 @@ class CloudTestsIntegrationTest(CiTestCase):
         integration_testdir = os.path.sep.join(
             [testsdir, 'cloud_tests', 'testcases'])
         errors = []
-        out, _ = subp(['find', integration_testdir, '-name', '*yaml'])
-        for filename in out.splitlines():
+
+        yaml_files = []
+        for root, _dirnames, filenames in os.walk(integration_testdir):
+            yaml_files.extend([os.path.join(root, f)
+                               for f in filenames if f.endswith(".yaml")])
+        self.assertTrue(len(yaml_files) > 0)
+
+        for filename in yaml_files:
             test_cfg = safe_load(open(filename))
             cloud_config = test_cfg.get('cloud_config')
             if cloud_config: