Merge ~smoser/cloud-init:feature/integration-execute-with-string into cloud-init:master

[Scott Moser]

tests: execute: support command as a string, change default env parm.

If a string is passed to execute, then invoke 'sh', '-c', 'string'.
That allows the less verbose execution of simple commands:
  image.execute("ls /run")
compared to the more explicit but longer winded:
  image.execute(["ls", "/run"])

If 'env' was ever modified in execute or a method that it called,
then the next invocation's default value would be changed. Instead
use None and then set to a new empty dict in the method.

[Joshua Powers (powersj)]

+1 thanks for this it makes it a lot easier on simple commands.

review: Approve

[Server Team CI bot (server-team-bot)]

FAILED: Continuous integration, rev:bfcb291233812bdd34aed9b798d3330cf01d9a92
https://jenkins.ubuntu.com/server/job/cloud-init-ci/276/
Executed test runs:
    SUCCESS: Checkout
    FAILED: Unit & Style Tests

Click here to trigger a rebuild:
https://jenkins.ubuntu.com/server/job/cloud-init-ci/276/rebuild

review: Needs Fixing (continuous-integration)

[Scott Moser (smoser)]

rejected, this was largely pulled into
 https://code.launchpad.net/~powersj/cloud-init/+git/cloud-init/+merge/330535

Unmerged commits

bfcb291... by Scott Moser on 2017-09-08

tests: execute: support command as a string, change default env parm.

If a string is passed to execute, then invoke 'sh', '-c', 'string'.
That allows the less verbose execution of simple commands:
  image.execute("ls /run")
compared to the more explicit but longer winded:
  image.execute(["ls", "/run"])

If 'env' was ever modified in execute or a method that it called,
then the next invocation's default value would be changed. Instead
use None and then set to a new empty dict in the method.

diff --git a/tests/cloud_tests/instances/base.py b/tests/cloud_tests/instances/base.py
index 959e9cc..1af3571 100644
--- a/tests/cloud_tests/instances/base.py
+++ b/tests/cloud_tests/instances/base.py
@@ -23,7 +23,7 @@ class Instance(object):
         self.config = config
         self.features = features
 
-    def execute(self, command, stdout=None, stderr=None, env={},
+    def execute(self, command, stdout=None, stderr=None, env=None,
                 rcs=None, description=None):
         """Execute command in instance, recording output, error and exit code.
 
@@ -31,6 +31,7 @@ class Instance(object):
         target filesystem being available at /.
 
         @param command: the command to execute as root inside the image
+           if command is an string, then it will be executed as: [sh, -c, command]
         @param stdout, stderr: file handles to write output and error to
         @param env: environment variables
         @param rcs: allowed return codes from command
diff --git a/tests/cloud_tests/instances/lxd.py b/tests/cloud_tests/instances/lxd.py
index b9c2cc6..6b72d62 100644
--- a/tests/cloud_tests/instances/lxd.py
+++ b/tests/cloud_tests/instances/lxd.py
@@ -31,7 +31,7 @@ class LXDInstance(base.Instance):
         self._pylxd_container.sync()
         return self._pylxd_container
 
-    def execute(self, command, stdout=None, stderr=None, env={},
+    def execute(self, command, stdout=None, stderr=None, env=None,
                 rcs=None, description=None):
         """Execute command in instance, recording output, error and exit code.
 
@@ -46,6 +46,11 @@ class LXDInstance(base.Instance):
         @param description: purpose of command
         @return_value: tuple containing stdout data, stderr data, exit code
         """
+        if env is None:
+            env = {}
+        if isinstance(command, str):
+            command = ["sh", "-c", command]
+
         # ensure instance is running and execute the command
         self.start()
         res = self.pylxd_container.execute(command, environment=env)