diff --git a/compose/parallel.py b/compose/parallel.py
index 879d183e8..c629a1abf 100644
--- a/compose/parallel.py
+++ b/compose/parallel.py
@@ -32,8 +32,8 @@ def parallel_execute(objects, func, get_name, msg, get_deps=None):
 
     done = 0
     errors = {}
+    results = []
     error_to_reraise = None
-    returned = [None] * len(objects)
 
     while done < len(objects):
         try:
@@ -46,14 +46,13 @@ def parallel_execute(objects, func, get_name, msg, get_deps=None):
 
         if exception is None:
             writer.write(get_name(obj), 'done')
-            returned[objects.index(obj)] = result
+            results.append(result)
         elif isinstance(exception, APIError):
             errors[get_name(obj)] = exception.explanation
             writer.write(get_name(obj), 'error')
         else:
             errors[get_name(obj)] = exception
             error_to_reraise = exception
-
         done += 1
 
     for obj_name, error in errors.items():
@@ -62,7 +61,7 @@ def parallel_execute(objects, func, get_name, msg, get_deps=None):
     if error_to_reraise:
         raise error_to_reraise
 
-    return returned
+    return results
 
 
 def _no_deps(x):
@@ -74,9 +73,8 @@ def setup_queue(objects, func, get_deps, get_name):
         get_deps = _no_deps
 
     results = Queue()
-
-    started = set()   # objects, threads were started for
-    finished = set()  # already finished objects
+    started = set()   # objects being processed
+    finished = set()  # objects which have been processed
 
     def do_op(obj):
         try:
@@ -96,11 +94,9 @@ def setup_queue(objects, func, get_deps, get_name):
         )
 
     def feed():
-        ready_objects = [o for o in objects if ready(o)]
-        for obj in ready_objects:
+        for obj in filter(ready, objects):
             started.add(obj)
-            t = Thread(target=do_op,
-                       args=(obj,))
+            t = Thread(target=do_op, args=(obj,))
             t.daemon = True
             t.start()
 
diff --git a/tests/integration/state_test.py b/tests/integration/state_test.py
index 36099d2dd..07b28e784 100644
--- a/tests/integration/state_test.py
+++ b/tests/integration/state_test.py
@@ -38,8 +38,8 @@ class BasicProjectTest(ProjectTestCase):
         super(BasicProjectTest, self).setUp()
 
         self.cfg = {
-            'db': {'image': 'busybox:latest'},
-            'web': {'image': 'busybox:latest'},
+            'db': {'image': 'busybox:latest', 'command': 'top'},
+            'web': {'image': 'busybox:latest', 'command': 'top'},
         }
 
     def test_no_change(self):