EC2 - Error when passing in TagSpec with 0 tags (#5216)

moto/ec2/exceptions.py

@@ -461,6 +461,13 @@ class InvalidParameterValueError(EC2ClientError):
         )
 
 
+class EmptyTagSpecError(EC2ClientError):
+    def __init__(self):
+        super().__init__(
+            "InvalidParameterValue", "Tag specification must have at least one tag"
+        )
+
+
 class InvalidParameterValueErrorTagNull(EC2ClientError):
     def __init__(self):
         super().__init__(

moto/ec2/responses/_base_response.py

@@ -1,4 +1,5 @@
 from moto.core.responses import BaseResponse
+from ..exceptions import EmptyTagSpecError
 from ..utils import convert_tag_spec
 
 
@@ -12,5 +13,10 @@ class EC2BaseResponse(BaseResponse):
     def _parse_tag_specification(self):
         # [{"ResourceType": _type, "Tag": [{"Key": k, "Value": v}, ..]}]
         tag_spec_set = self._get_multi_param("TagSpecification")
+        # If we do not pass any Tags, this method will convert this to [_type] instead
+        if isinstance(tag_spec_set, list) and any(
+            [isinstance(spec, str) for spec in tag_spec_set]
+        ):
+            raise EmptyTagSpecError
         # {_type: {k: v, ..}}
         return convert_tag_spec(tag_spec_set)

tests/test_ec2/test_tags.py

@@ -401,6 +401,26 @@ def test_create_snapshot_with_tags():
     assert snapshot["Tags"] == expected_tags
 
 
+@mock_ec2
+def test_create_volume_without_tags():
+    client = boto3.client("ec2", "us-east-1")
+    with pytest.raises(ClientError) as exc:
+        client.create_volume(
+            AvailabilityZone="us-east-1a",
+            Encrypted=False,
+            Size=40,
+            TagSpecifications=[
+                {
+                    "ResourceType": "volume",
+                    "Tags": [],
+                }
+            ],
+        )
+    err = exc.value.response["Error"]
+    err["Code"].should.equal("InvalidParameterValue")
+    err["Message"].should.equal("Tag specification must have at least one tag")
+
+
 @mock_ec2
 def test_create_tag_empty_resource():
     # create ec2 client in us-west-1