Stop 'rm' and 'ps' listing services not defined in the current file

If you have an alternate YAML file with different services defined,
containers for those services will be shown in `docker-compose ps` even
if you don't pass that file in.

Furthermore, `docker-compose rm` will claim that it's going to remove
them, but actually won't.

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

compose/project.py

@@ -288,6 +288,9 @@ class Project(object):
     def containers(self, service_names=None, stopped=False, one_off=False):
         if service_names:
             self.validate_service_names(service_names)
+        else:
+            service_names = self.service_names
+
         containers = [
             Container.from_ps(self.client, container)
             for container in self.client.containers(
@@ -295,8 +298,6 @@ class Project(object):
                 filters={'label': self.labels(one_off=one_off)})]
 
         def matches_service_names(container):
-            if not service_names:
-                return True
             return container.labels.get(LABEL_SERVICE) in service_names
 
         if not containers:

tests/integration/project_test.py

@@ -35,6 +35,21 @@ class ProjectTest(DockerClientTestCase):
             [c.name for c in containers],
             ['composetest_web_1'])
 
+    def test_containers_with_extra_service(self):
+        web = self.create_service('web')
+        web_1 = web.create_container()
+
+        db = self.create_service('db')
+        db_1 = db.create_container()
+
+        self.create_service('extra').create_container()
+
+        project = Project('composetest', [web, db], self.client)
+        self.assertEqual(
+            set(project.containers(stopped=True)),
+            set([web_1, db_1]),
+        )
+
     def test_volumes_from_service(self):
         service_dicts = build_service_dicts({
             'data': {