From a04ef583864ff2e572a06e30fde6c1d175e56317 Mon Sep 17 00:00:00 2001
From: Guilherme de Amorim <guamorim@usp.br>
Date: Thu, 25 Jan 2024 19:38:37 -0300
Subject: [PATCH] SageMaker: correct describe_model_package_group does not
 exist msg (#7246)

---
 Makefile                                        |  1 +
 moto/sagemaker/models.py                        |  8 +++++++-
 .../test_sagemaker_model_package_groups.py      | 17 +++++++++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index aa403f097..9c80b4c46 100644
--- a/Makefile
+++ b/Makefile
@@ -32,6 +32,7 @@ lint:
 
 format:
 	black moto/ tests/
+	ruff --fix moto/ tests/
 
 test-only:
 	rm -f .coverage
diff --git a/moto/sagemaker/models.py b/moto/sagemaker/models.py
index 241dbdfa3..a828ee3a2 100644
--- a/moto/sagemaker/models.py
+++ b/moto/sagemaker/models.py
@@ -3334,8 +3334,14 @@ class SageMakerModelBackend(BaseBackend):
     ) -> ModelPackageGroup:
         model_package_group = self.model_package_groups.get(model_package_group_name)
         if model_package_group is None:
+            model_package_group_arn = arn_formatter(
+                region_name=self.region_name,
+                account_id=self.account_id,
+                _type="model-package-group",
+                _id=f"{model_package_group_name}",
+            )
             raise ValidationError(
-                f"Model package group {model_package_group_name} not found"
+                f"ModelPackageGroup {model_package_group_arn} does not exist."
             )
         return model_package_group
 
diff --git a/tests/test_sagemaker/test_sagemaker_model_package_groups.py b/tests/test_sagemaker/test_sagemaker_model_package_groups.py
index 15ba43a8a..d9d50a261 100644
--- a/tests/test_sagemaker/test_sagemaker_model_package_groups.py
+++ b/tests/test_sagemaker/test_sagemaker_model_package_groups.py
@@ -4,6 +4,8 @@ from datetime import datetime
 from unittest import SkipTest
 
 import boto3
+import pytest
+from botocore.exceptions import ClientError
 from dateutil.tz import tzutc  # type: ignore
 from freezegun import freeze_time
 
@@ -193,6 +195,21 @@ def test_describe_model_package_group():
     assert resp["CreationTime"] == datetime(2020, 1, 1, 0, 0, 0, tzinfo=tzutc())
 
 
+@mock_sagemaker
+def test_describe_model_package_group_not_exists():
+    if settings.TEST_SERVER_MODE:
+        raise SkipTest("Can't freeze time in ServerMode")
+    client = boto3.client("sagemaker", region_name="eu-west-1")
+
+    with pytest.raises(ClientError) as e:
+        client.describe_model_package_group(
+            ModelPackageGroupName="test-model-package-group"
+        )
+
+    assert e.value.response["Error"]["Code"] == "ValidationException"
+    assert "does not exist" in e.value.response["Error"]["Message"]
+
+
 @mock_sagemaker
 def test_list_tags_model_package_group():
     region_name = "eu-west-1"