From 0953ddde51a89ffc1342ab30548f79705f4ba854 Mon Sep 17 00:00:00 2001
From: Nuwan Goonasekera <nuwan.ag@gmail.com>
Date: Sat, 16 Sep 2017 12:26:43 +0530
Subject: [PATCH] Fix for instance public ip not being cleared on eip
 disassociation

---
 moto/ec2/models.py                          |  9 +--------
 tests/test_ec2/test_elastic_ip_addresses.py | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 21d9a1e36..545a9a3a3 100755
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -590,10 +590,6 @@ class Instance(TaggedEC2Resource, BotoInstance):
 
             self.attach_eni(use_nic, device_index)
 
-    def set_ip(self, ip_address):
-        # Should we be creating a new ENI?
-        self.nics[0].public_ip = ip_address
-
     def attach_eni(self, eni, device_index):
         device_index = int(device_index)
         self.nics[device_index] = eni
@@ -3047,8 +3043,6 @@ class ElasticAddressBackend(object):
                 eip.eni.public_ip = eip.public_ip
             if eip.domain == "vpc":
                 eip.association_id = random_eip_association_id()
-            if instance:
-                instance.set_ip(eip.public_ip)
 
             return eip
 
@@ -3082,10 +3076,9 @@ class ElasticAddressBackend(object):
         eip = eips[0]
 
         if eip.eni:
+            eip.eni.public_ip = None
             if eip.eni.instance and eip.eni.instance._state.name == "running":
                 eip.eni.check_auto_public_ip()
-            else:
-                eip.eni.public_ip = None
             eip.eni = None
 
         eip.instance = None
diff --git a/tests/test_ec2/test_elastic_ip_addresses.py b/tests/test_ec2/test_elastic_ip_addresses.py
index 824c9402c..709bdc33b 100644
--- a/tests/test_ec2/test_elastic_ip_addresses.py
+++ b/tests/test_ec2/test_elastic_ip_addresses.py
@@ -180,13 +180,31 @@ def test_eip_boto3_vpc_association():
         'SubnetId': subnet_res['Subnet']['SubnetId']
     })[0]
     allocation_id = client.allocate_address(Domain='vpc')['AllocationId']
+    address = service.VpcAddress(allocation_id)
+    address.load()
+    address.association_id.should.be.none
+    address.instance_id.should.be.empty
+    address.network_interface_id.should.be.empty
     association_id = client.associate_address(
         InstanceId=instance.id,
         AllocationId=allocation_id,
         AllowReassociation=False)
     instance.load()
+    address.reload()
+    address.association_id.should_not.be.none
     instance.public_ip_address.should_not.be.none
     instance.public_dns_name.should_not.be.none
+    address.network_interface_id.should.equal(instance.network_interfaces_attribute[0].get('NetworkInterfaceId'))
+    address.public_ip.should.equal(instance.public_ip_address)
+    address.instance_id.should.equal(instance.id)
+
+    client.disassociate_address(AssociationId=address.association_id)
+    instance.reload()
+    address.reload()
+    instance.public_ip_address.should.be.none
+    address.network_interface_id.should.be.empty
+    address.association_id.should.be.none
+    address.instance_id.should.be.empty
 
 
 @mock_ec2_deprecated