Fix EC2 response tags. Closes #37.

tests/test_ec2/test_tags.py

@@ -1,3 +1,5 @@
+import itertools
+
 import boto
 import sure  # flake8: noqa
 
@@ -19,3 +21,17 @@ def test_instance_launch_and_terminate():
 
     instance.remove_tag("a key")
     conn.get_all_tags().should.have.length_of(0)
+
+
+@mock_ec2
+def test_instance_launch_and_retrieve_all_instances():
+    conn = boto.connect_ec2('the_key', 'the_secret')
+    reservation = conn.run_instances('ami-1234abcd')
+    instance = reservation.instances[0]
+
+    instance.add_tag("a key", "some value")
+    chain = itertools.chain.from_iterable
+    existing_instances = list(chain([reservation.instances for reservation in conn.get_all_instances()]))
+    existing_instances.should.have.length_of(1)
+    existing_instance = existing_instances[0]
+    existing_instance.tags["a key"].should.equal("some value")