Don't assume VPCs have tags

senza/manaus/ec2.py

@@ -1,5 +1,5 @@
 from collections import OrderedDict
-from typing import Dict, List, Iterator
+from typing import Dict, List, Iterator, Optional
 
 import boto3
 
@@ -16,9 +16,10 @@ class EC2VPC:
     def __init__(self,
                  vpc_id: str,
                  is_default: bool,
-                 tags: List[Dict[str, str]]):
+                 tags: Optional[List[Dict[str, str]]]):
         self.vpc_id = vpc_id
         self.is_default = is_default
+        tags = tags or []  # type: List[Dict[str, str]]
         self.tags = OrderedDict([(t['Key'], t['Value']) for t in tags])  # type: Dict[str, str]
 
         self.name = self.tags.get('Name', self.vpc_id)

tests/test_manaus/test_ec2.py

@@ -37,6 +37,11 @@ def test_get_default_vpc(monkeypatch):
     mock_vpc3.is_default = False
     mock_vpc3.tags = []
 
+    mock_vpc4 = MagicMock()
+    mock_vpc4.vpc_id = 'vpc-id4'
+    mock_vpc4.is_default = True
+    mock_vpc4.tags = None
+
     m_resource = MagicMock()
     m_resource.return_value = m_resource
     monkeypatch.setattr('boto3.resource', m_resource)
@@ -59,11 +64,16 @@ def test_get_default_vpc(monkeypatch):
         ec2.get_default_vpc()
     assert str(exc_info.value) == "Can't find any VPC!"
 
-    # no vpcs
+    # multiple vpcs
     m_resource.vpcs.all.return_value = [mock_vpc2, mock_vpc3]
     with pytest.raises(VPCError) as exc_info:
         ec2.get_default_vpc()
 
+    # no tags in vpc return default vpc
+    m_resource.vpcs.all.return_value = [mock_vpc4, mock_vpc2]
+    vpc3 = ec2.get_default_vpc()
+    assert vpc3.vpc_id == 'vpc-id4'
+
     assert str(exc_info.value) == ("Multiple VPCs are only supported if one "
                                    "VPC is the default VPC (IsDefault=true)!")