diff --git a/ondivi/__main__.py b/ondivi/__main__.py
index b37c4ad..5b6cf6e 100644
--- a/ondivi/__main__.py
+++ b/ondivi/__main__.py
@@ -157,14 +157,14 @@ def main() -> None:
         ]),
     )
     args = parser.parse_args()
-    violations = sys.stdin.read().strip().splitlines()
-    sys.stdout.write('\n'.join(
-        controller(
-            Repo('.').git.diff('--unified=0', args.baseline),
-            violations,
-        ),
-    ))
+    violations = controller(
+        Repo('.').git.diff('--unified=0', args.baseline),
+        sys.stdin.read().strip().splitlines(),
+    )
+    sys.stdout.write('\n'.join(violations))
     sys.stdout.write('\n')
+    if violations:
+        sys.exit(1)
 
 
 if __name__ == '__main__':
diff --git a/tests/it/test_app.py b/tests/it/test_app.py
index 689a8cd..1390aba 100644
--- a/tests/it/test_app.py
+++ b/tests/it/test_app.py
@@ -63,9 +63,10 @@ def test_gitpython_versions(version: str) -> None:
         ).stdout,
         stdout=subprocess.PIPE,
         check=False,
-    ).stdout.decode('utf-8').strip()
+    )
 
-    assert got == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.stdout.decode('utf-8').strip() == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.returncode == 1
 
 
 @pytest.mark.usefixtures('_test_repo')
@@ -79,9 +80,10 @@ def test() -> None:
         ).stdout,
         stdout=subprocess.PIPE,
         check=False,
-    ).stdout.decode('utf-8').strip()
+    )
 
-    assert got == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.stdout.decode('utf-8').strip() == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.returncode == 1
 
 
 @pytest.mark.usefixtures('_test_repo')
@@ -95,9 +97,10 @@ def test_baseline_default() -> None:
         ).stdout,
         stdout=subprocess.PIPE,
         check=False,
-    ).stdout.decode('utf-8').strip()
+    )
 
-    assert got == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.stdout.decode('utf-8').strip() == 'file.py:4:80: E501 line too long (119 > 79 characters)'
+    assert got.returncode == 1
 
 
 @pytest.mark.usefixtures('_test_repo')
@@ -111,12 +114,13 @@ def test_ruff() -> None:
         ).stdout,
         stdout=subprocess.PIPE,
         check=False,
-    ).stdout.decode('utf-8').strip()
+    )
 
-    assert got == '\n'.join([
+    assert got.stdout.decode('utf-8').strip() == '\n'.join([
         'file.py:4:5: T201 `print` found',
         'file.py:4:11: Q000 [*] Single quotes found but double quotes preferred',
         'file.py:4:89: E501 Line too long (119 > 88)',
         'Found 13 errors.',
         '[*] 4 fixable with the `--fix` option (4 hidden fixes can be enabled with the `--unsafe-fixes` option).',
     ])
+    assert got.returncode == 1