Add test for shell command

tests/components/test_shell_command.py

@@ -0,0 +1,38 @@
+"""
+tests.test_shell_command
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Tests demo component.
+"""
+import os
+import tempfile
+import unittest
+
+from homeassistant import core
+from homeassistant.components import shell_command
+
+
+class TestShellCommand(unittest.TestCase):
+    """ Test the demo module. """
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.hass = core.HomeAssistant()
+
+    def tearDown(self):  # pylint: disable=invalid-name
+        """ Stop down stuff we started. """
+        self.hass.stop()
+
+    def test_executing_service(self):
+        """ Test if able to call a configured service. """
+        with tempfile.TemporaryDirectory() as tempdirname:
+            path = os.path.join(tempdirname, 'called.txt')
+            shell_command.setup(self.hass, {
+                'shell_command': {
+                    'test_service': "touch {}".format(path)
+                }
+            })
+
+            self.hass.services.call('shell_command', 'test_service',
+                                    blocking=True)
+
+            self.assertTrue(os.path.isfile(path))