Add ROS service for executing shell commands (#210)

* Add ROS service for executing shell commands

* Show image version on index web page

* Add test for exec service

* Add shell node to clover.launch

* Remake exec handling, consider exit code and exec failures

clover/test/basic.py

@@ -2,6 +2,7 @@
 import rospy
 import pytest
 from mavros_msgs.msg import State
+from clover import srv
 
 @pytest.fixture()
 def node():
@@ -27,3 +28,19 @@ def test_simple_offboard_services_available():
 def test_web_video_server(node):
     import urllib2
     urllib2.urlopen("http://localhost:8080").read()
+
+def test_shell(node):
+    execute = rospy.ServiceProxy('exec', srv.Execute)
+    execute.wait_for_service(5)
+
+    res = execute(cmd='echo foo')
+    assert res.code == 0
+    assert res.output == 'foo\n'
+
+    res = execute(cmd='foo')
+    assert res.code == 32512
+    assert res.output == ''
+
+    res = execute(cmd='ls foo')
+    assert res.code == 512
+    assert res.output == ''