use static localhost binding for molecule

molecule/ec2-centos-7/playbook.yml

@@ -9,6 +9,7 @@
         baseurl: "http://download.fedoraproject.org/pub/epel/$releasever/$basearch/"
         gpgkey: "http://download.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-$releasever/"
         enabled: True
+    mosquitto_bind_address: "127.0.0.1"
 
   roles:
     - role: xoxys.yum

molecule/ec2-centos-7/tests/test_default.py

@@ -22,6 +22,4 @@ def test_mosquitto_running_and_enabled(host):
 
 def test_mosquitto_socket(host):
     # Verify the socket is listening for HTTP traffic
-    address = host.ansible("debug", "var=ansible_default_ipv4.address")
-    assert host.socket(
-        "tcp://{address}:8883".format(address=address)).is_listening
+    assert host.socket("tcp://127.0.0.1:8883").is_listening