Fix DescribeImages to throw error if AMI requested does not exist

moto/ec2/exceptions.py

@@ -1,4 +1,4 @@
 class InvalidIdError(RuntimeError):
-    def __init__(self, instance_id):
+    def __init__(self, id_value):
         super(InvalidIdError, self).__init__()
-        self.instance_id = instance_id
+        self.id = id_value

moto/ec2/models.py

@@ -222,6 +222,8 @@ class AmiBackend(object):
     def describe_images(self, ami_ids=None):
         if ami_ids:
             images = [image for image in self.amis.values() if image.id in ami_ids]
+            for missing_ami in set(ami_ids) - set(ami.id for ami in images):
+                raise InvalidIdError(missing_ami)
         else:
             images = self.amis.values()
         return images

moto/ec2/responses/amis.py

@@ -2,6 +2,7 @@ from jinja2 import Template
 
 from moto.core.responses import BaseResponse
 from moto.ec2.models import ec2_backend
+from moto.ec2.exceptions import InvalidIdError
 from moto.ec2.utils import instance_ids_from_querystring, image_ids_from_querystring
 
 
@@ -35,9 +36,14 @@ class AmisResponse(BaseResponse):
 
     def describe_images(self):
         ami_ids = image_ids_from_querystring(self.querystring)
-        images = ec2_backend.describe_images(ami_ids=ami_ids)
-        template = Template(DESCRIBE_IMAGES_RESPONSE)
-        return template.render(images=images)
+        try:
+            images = ec2_backend.describe_images(ami_ids=ami_ids)
+        except InvalidIdError as exc:
+            template = Template(DESCRIBE_IMAGES_INVALID_IMAGE_ID_RESPONSE)
+            return template.render(image_id=exc.id), dict(status=400)
+        else:
+            template = Template(DESCRIBE_IMAGES_RESPONSE)
+            return template.render(images=images)
 
     def modify_image_attribute(self):
         raise NotImplementedError('AMIs.modify_image_attribute is not yet implemented')
@@ -101,6 +107,11 @@ DESCRIBE_IMAGE_RESPONSE = """<DescribeImageAttributeResponse xmlns="http://ec2.a
    </{{key }}>
 </DescribeImageAttributeResponse>"""
 
+
+DESCRIBE_IMAGES_INVALID_IMAGE_ID_RESPONSE = """<?xml version="1.0" encoding="UTF-8"?>
+<Response><Errors><Error><Code>InvalidAMIID.NotFound</Code><Message>The image id '[{{ image_id }}]' does not exist</Message></Error></Errors><RequestID>59dbff89-35bd-4eac-99ed-be587EXAMPLE</RequestID></Response>
+"""
+
 DEREGISTER_IMAGE_RESPONSE = """<DeregisterImageResponse xmlns="http://ec2.amazonaws.com/doc/2012-12-01/">
   <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId>
   <return>{{ success }}</return>

moto/ec2/responses/instances.py

@@ -15,7 +15,7 @@ class InstanceResponse(BaseResponse):
                 reservations = ec2_backend.get_reservations_by_instance_ids(instance_ids)
             except InvalidIdError as exc:
                 template = Template(EC2_INVALID_INSTANCE_ID)
-                return template.render(instance_id=exc.instance_id), dict(status=400)
+                return template.render(instance_id=exc.id), dict(status=400)
         else:
             reservations = ec2_backend.all_reservations(make_copy=True)