[primer] Fix a silent fail when no command were given (#7185)

Co-authored-by: Daniël van Noord <13665637+DanielNoord@users.noreply.github.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/testutils/_primer/test_primer.py b/tests/testutils/_primer/test_primer.py
index 3093fa98e..28416de69 100644
--- a/tests/testutils/_primer/test_primer.py
+++ b/tests/testutils/_primer/test_primer.py
@@ -10,6 +10,7 @@ from pathlib import Path
 from unittest.mock import patch
 
 import pytest
+from _pytest.capture import CaptureFixture
 
 from pylint.constants import IS_PYPY
 from pylint.testutils._primer.primer import Primer
@@ -25,6 +26,16 @@ PRIMER_CURRENT_INTERPRETER = (3, 10)
 DEFAULT_ARGS = ["python tests/primer/__main__.py", "compare", "--commit=v2.14.2"]
 
 
+@pytest.mark.parametrize("args", [[], ["wrong_command"]])
+def test_primer_launch_bad_args(args: list[str], capsys: CaptureFixture) -> None:
+    with pytest.raises(SystemExit):
+        with patch("sys.argv", ["python tests/primer/__main__.py"] + args):
+            Primer(PRIMER_DIRECTORY, PACKAGES_TO_PRIME_PATH).run()
+    out, err = capsys.readouterr()
+    assert not out
+    assert "usage: Pylint Primer" in err
+
+
 @pytest.mark.skipif(
     sys.platform in {"win32", "darwin"},
     reason=(