Fix AWS instance_profile tests for moto v4

Moto v4 has added support for iam instance profiles, which means
our tests are now failing since we have two tests that request
an instance be created with a profile association, but the profile
did not exist in moto due to the lack of support.

Now that support has been added, we create a dummy instance profile
and use that for the association.  We can now also validate that
the association was made as expected.

Change-Id: I2839b7e1536a6305e44678dc9b22c71f3eb55677

nodepool/tests/fixtures/aws/aws.yaml

@@ -93,7 +93,7 @@ providers:
             instance-type: t3.medium
             key-name: zuul
             iam-instance-profile:
-              arn: arn:aws:iam::123456789012:instance-profile/not-a-real-profile
+              arn: {instance_profile_arn}
           - name: ubuntu1404-with-tags
             cloud-image: ubuntu1404
             instance-type: t3.medium

nodepool/tests/unit/test_driver_aws.py

@@ -21,7 +21,7 @@ import urllib.parse
 
 import boto3
 import botocore.exceptions
-from moto import mock_ec2, mock_s3
+from moto import mock_ec2, mock_s3, mock_iam
 import testtools
 
 from nodepool import config as nodepool_config
@@ -90,6 +90,7 @@ class TestDriverAws(tests.DBTestCase):
     log = logging.getLogger("nodepool.TestDriverAws")
     mock_ec2 = mock_ec2()
     mock_s3 = mock_s3()
+    mock_iam = mock_iam()
 
     def setUp(self):
         super().setUp()
@@ -108,11 +109,13 @@ class TestDriverAws(tests.DBTestCase):
         self.fake_aws = FakeAws()
         self.mock_ec2.start()
         self.mock_s3.start()
+        self.mock_iam.start()
 
         self.ec2 = boto3.resource('ec2', region_name='us-west-2')
         self.ec2_client = boto3.client('ec2', region_name='us-west-2')
         self.s3 = boto3.resource('s3', region_name='us-west-2')
         self.s3_client = boto3.client('s3', region_name='us-west-2')
+        self.iam = boto3.resource('iam', region_name='us-west-2')
         self.s3.create_bucket(
             Bucket='nodepool',
             CreateBucketConfiguration={'LocationConstraint': 'us-west-2'})
@@ -142,6 +145,11 @@ class TestDriverAws(tests.DBTestCase):
                 CidrBlock='203.0.113.128/25', VpcId=self.vpc['Vpc']['VpcId'])
             self.subnet_id = self.subnet['Subnet']['SubnetId']
 
+        profile = self.iam.create_instance_profile(
+            InstanceProfileName='not-a-real-profile')
+        self.instance_profile_name = profile.name
+        self.instance_profile_arn = profile.arn
+
         self.security_group = self.ec2_client.create_security_group(
             GroupName='zuul-nodes', VpcId=self.vpc['Vpc']['VpcId'],
             Description='Zuul Nodes')
@@ -163,6 +171,8 @@ class TestDriverAws(tests.DBTestCase):
     def setup_config(self, *args, **kw):
         kw['subnet_id'] = self.subnet_id
         kw['security_group_id'] = self.security_group_id
+        kw['instance_profile_name'] = self.instance_profile_name
+        kw['instance_profile_arn'] = self.instance_profile_arn
         return super().setup_config(*args, **kw)
 
     def patchAdapter(self, quotas=None):
@@ -443,14 +453,18 @@ class TestDriverAws(tests.DBTestCase):
             response['UserData']['Value']).decode()
         self.assertEqual('fake-user-data', userdata)
 
-    # Note(avass): moto does not yet support attaching an instance profile
-    # but these two at least tests to make sure that the instances 'starts'
     def test_aws_iam_instance_profile_name(self):
         req = self.requestNode('aws/aws.yaml',
                                'ubuntu1404-iam-instance-profile-name')
         node = self.assertSuccess(req)
         self.assertEqual(node.host_keys, ['ssh-rsa FAKEKEY'])
         self.assertEqual(node.image_id, 'ubuntu1404')
+        associations = self.ec2_client.\
+            describe_iam_instance_profile_associations()[
+                "IamInstanceProfileAssociations"]
+        self.assertEqual(node.external_id, associations[0]['InstanceId'])
+        self.assertEqual(self.instance_profile_arn,
+                         associations[0]['IamInstanceProfile']['Arn'])
 
     def test_aws_iam_instance_profile_arn(self):
         req = self.requestNode('aws/aws.yaml',
@@ -458,6 +472,12 @@ class TestDriverAws(tests.DBTestCase):
         node = self.assertSuccess(req)
         self.assertEqual(node.host_keys, ['ssh-rsa FAKEKEY'])
         self.assertEqual(node.image_id, 'ubuntu1404')
+        associations = self.ec2_client.\
+            describe_iam_instance_profile_associations()[
+                "IamInstanceProfileAssociations"]
+        self.assertEqual(node.external_id, associations[0]['InstanceId'])
+        self.assertEqual(self.instance_profile_arn,
+                         associations[0]['IamInstanceProfile']['Arn'])
 
     def test_aws_private_ip(self):
         req = self.requestNode('aws/private-ip.yaml', 'ubuntu1404-private-ip')