From 4a402b01cfdd8ffe8947e384471bd7a31faa6d86 Mon Sep 17 00:00:00 2001
From: mickeypash <pashov.m@gmail.com>
Date: Mon, 23 Oct 2017 19:12:49 +0100
Subject: [PATCH] Correct response when trying to delete a volume that is
 attached to an EC2 instance. Created a VolumeInUse error and did a simple
 check on the delete_volume method.

---
 moto/ec2/exceptions.py | 9 +++++++++
 moto/ec2/models.py     | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/moto/ec2/exceptions.py b/moto/ec2/exceptions.py
index e5432baf7..ae279d5b2 100644
--- a/moto/ec2/exceptions.py
+++ b/moto/ec2/exceptions.py
@@ -244,6 +244,15 @@ class InvalidVolumeAttachmentError(EC2ClientError):
             .format(volume_id, instance_id))
 
 
+class VolumeInUseError(EC2ClientError):
+
+    def __init__(self, volume_id, instance_id):
+        super(VolumeInUseError, self).__init__(
+            "VolumeInUse",
+            "Volume {0} is currently attached to {1}"
+            .format(volume_id, instance_id))
+
+
 class InvalidDomainError(EC2ClientError):
 
     def __init__(self, domain):
diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 7fa7e1009..011258520 100755
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -45,6 +45,7 @@ from .exceptions import (
     InvalidAMIAttributeItemValueError,
     InvalidSnapshotIdError,
     InvalidVolumeIdError,
+    VolumeInUseError,
     InvalidVolumeAttachmentError,
     InvalidDomainError,
     InvalidAddressError,
@@ -1813,6 +1814,10 @@ class EBSBackend(object):
 
     def delete_volume(self, volume_id):
         if volume_id in self.volumes:
+            volume = self.volumes[volume_id]
+            instance_id = volume.attachment.instance.id
+            if volume.attachment is not None:
+                raise VolumeInUseError(volume_id, instance_id)
             return self.volumes.pop(volume_id)
         raise InvalidVolumeIdError(volume_id)