From 82214d2bc2a83d17217bdac87b1207fb31e3e256 Mon Sep 17 00:00:00 2001
From: Steve Pulec <spulec@gmail.com>
Date: Sat, 28 Mar 2015 14:30:30 -0400
Subject: [PATCH] Fix bug with empty string for instance vpc_id. Closes #337.

---
 moto/ec2/responses/instances.py  | 24 ++++++++++++++++--------
 tests/test_ec2/test_instances.py |  5 +++--
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/moto/ec2/responses/instances.py b/moto/ec2/responses/instances.py
index f7c03206d..6a3ff35f5 100644
--- a/moto/ec2/responses/instances.py
+++ b/moto/ec2/responses/instances.py
@@ -214,8 +214,10 @@ EC2_RUN_INSTANCES = """<RunInstancesResponse xmlns="http://ec2.amazonaws.com/doc
             <state>enabled</state>
           </monitoring>
           {% if instance.nics %}
-            <subnetId>{{ instance.nics[0].subnet.id }}</subnetId>
-            <vpcId>{{ instance.nics[0].subnet.vpc_id }}</vpcId>
+            {% if instance.nics[0].subnet %}
+              <subnetId>{{ instance.nics[0].subnet.id }}</subnetId>
+              <vpcId>{{ instance.nics[0].subnet.vpc_id }}</vpcId>
+            {% endif %}
             <privateIpAddress>{{ instance.private_ip }}</privateIpAddress>
             {% if instance.public_ip %}
                 <ipAddress>{{ instance.public_ip }}</ipAddress>
@@ -245,8 +247,10 @@ EC2_RUN_INSTANCES = """<RunInstancesResponse xmlns="http://ec2.amazonaws.com/doc
             {% for nic in instance.nics.values() %}
               <item>
                 <networkInterfaceId>{{ nic.id }}</networkInterfaceId>
-                <subnetId>{{ nic.subnet.id }}</subnetId>
-                <vpcId>{{ nic.subnet.vpc_id }}</vpcId>
+                {% if nic.subnet %}
+                  <subnetId>{{ nic.subnet.id }}</subnetId>
+                  <vpcId>{{ nic.subnet.vpc_id }}</vpcId>
+                {% endif %}
                 <description>Primary network interface</description>
                 <ownerId>111122223333</ownerId>
                 <status>in-use</status>
@@ -338,8 +342,10 @@ EC2_DESCRIBE_INSTANCES = """<DescribeInstancesResponse xmlns='http://ec2.amazona
                       <state>disabled</state>
                     </monitoring>
                     {% if instance.nics %}
-                      <subnetId>{{ instance.nics[0].subnet.id }}</subnetId>
-                      <vpcId>{{ instance.nics[0].subnet.vpc_id }}</vpcId>
+                      {% if instance.nics[0].subnet %}
+                        <subnetId>{{ instance.nics[0].subnet.id }}</subnetId>
+                        <vpcId>{{ instance.nics[0].subnet.vpc_id }}</vpcId>
+                      {% endif %}
                       <privateIpAddress>{{ instance.private_ip }}</privateIpAddress>
                       {% if instance.nics[0].public_ip %}
                           <ipAddress>{{ instance.nics[0].public_ip }}</ipAddress>
@@ -390,8 +396,10 @@ EC2_DESCRIBE_INSTANCES = """<DescribeInstancesResponse xmlns='http://ec2.amazona
                       {% for nic in instance.nics.values() %}
                         <item>
                           <networkInterfaceId>{{ nic.id }}</networkInterfaceId>
-                          <subnetId>{{ nic.subnet.id }}</subnetId>
-                          <vpcId>{{ nic.subnet.vpc_id }}</vpcId>
+                          {% if nic.subnet %}
+                            <subnetId>{{ nic.subnet.id }}</subnetId>
+                            <vpcId>{{ nic.subnet.vpc_id }}</vpcId>
+                          {% endif %}
                           <description>Primary network interface</description>
                           <ownerId>111122223333</ownerId>
                           <status>in-use</status>
diff --git a/tests/test_ec2/test_instances.py b/tests/test_ec2/test_instances.py
index 640a24eaf..5ee732d5e 100644
--- a/tests/test_ec2/test_instances.py
+++ b/tests/test_ec2/test_instances.py
@@ -54,6 +54,7 @@ def test_instance_launch_and_terminate():
     instances[0].id.should.equal(instance.id)
     instances[0].state.should.equal('running')
     instances[0].launch_time.should.equal("2014-01-01T05:00:00")
+    instances[0].vpc_id.should.equal(None)
 
     root_device_name = instances[0].root_device_name
     instances[0].block_device_mapping[root_device_name].status.should.equal('attached')
@@ -155,7 +156,7 @@ def test_get_instances_filtering_by_instance_type():
     reservations.should.have.length_of(2)
     reservations[0].instances.should.have.length_of(1)
     reservations[1].instances.should.have.length_of(1)
-    instance_ids = [ reservations[0].instances[0].id, 
+    instance_ids = [ reservations[0].instances[0].id,
                      reservations[1].instances[0].id ]
     set(instance_ids).should.equal(set([instance1.id, instance2.id]))
 
@@ -311,7 +312,7 @@ def test_get_instances_filtering_by_tag_value():
     reservations[0].instances[0].id.should.equal(instance1.id)
     reservations[0].instances[1].id.should.equal(instance2.id)
     reservations[0].instances[2].id.should.equal(instance3.id)
-    
+
     reservations = conn.get_all_instances(filters={'tag-value' : ['value2', 'bogus']})
     # get_all_instances should return both instances with one of the acceptable tag values
     reservations.should.have.length_of(1)