factor out function for getting top level directory of cloudinit (#1136)

Add a test helper to get top level directory

Many tests need to get the location of files & dirs within the cloud-init
project directory.

Tests implement this in various different ways, and often those ways
depend on the current working directory of the pytest invocation.
Create helper functions (and tests) that gets the path of the top
directory or any sub directory under the top directory. This function
does not depend on the environment.

1 files changed, 12 insertions, 8 deletions

diff --git a/tests/unittests/test_subp.py b/tests/unittests/test_subp.py
index ec513d01..572510d7 100644
--- a/tests/unittests/test_subp.py
+++ b/tests/unittests/test_subp.py
@@ -10,7 +10,7 @@ import stat
 from unittest import mock
 
 from cloudinit import subp, util
-from tests.unittests.helpers import CiTestCase
+from tests.unittests.helpers import CiTestCase, get_top_level_dir
 
 
 BASH = subp.which('bash')
@@ -232,13 +232,17 @@ class TestSubp(CiTestCase):
         the default encoding will be set to ascii.  In such an environment
         Popen(['command', 'non-ascii-arg']) would cause a UnicodeDecodeError.
         """
-        python_prog = '\n'.join([
-            'import json, sys',
-            'from cloudinit.subp import subp',
-            'data = sys.stdin.read()',
-            'cmd = json.loads(data)',
-            'subp(cmd, capture=False)',
-            ''])
+        python_prog = '\n'.join(
+            [
+                'import json, sys',
+                'sys.path.insert(0, "{}")'.format(get_top_level_dir()),
+                'from cloudinit.subp import subp',
+                'data = sys.stdin.read()',
+                'cmd = json.loads(data)',
+                'subp(cmd, capture=False)',
+                '',
+            ]
+        )
         cmd = [BASH, '-c', 'echo -n "$@"', '--',
                self.utf8_valid.decode("utf-8")]
         python_subp = [sys.executable, '-c', python_prog]