Add test of lefty usage

diff --git a/rtest/test_regression.py b/rtest/test_regression.py
index 2fbc48b2e6b4aafec1b8e911a9a60b4934d22145..61568b3498c464d15acbe1c9aab9ff2d08b90935 100644 (file)
--- a/rtest/test_regression.py
+++ b/rtest/test_regression.py
@@ -330,3 +330,15 @@ def test_1813():
       universal_newlines=True)
 
     assert 'Usage' in output, 'gvedit -? did not show usage'
+
+def test_1818():
+    '''
+    lefty -? should show usage
+    https://gitlab.com/graphviz/graphviz/-/issues/1813
+    '''
+
+    output = subprocess.check_output(['lefty', '-?'],
+      stderr=subprocess.STDOUT,
+      universal_newlines=True)
+
+    assert 'Usage' in output, 'lefty -? did not show usage'