Guard against empty ParseExpressions

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/test_unit.py b/tests/test_unit.py
index b4362d3..ca9b474 100644
--- a/tests/test_unit.py
+++ b/tests/test_unit.py
@@ -8484,6 +8484,14 @@ class Test02_WithoutPackrat(ppt.TestParseResultsAsserts, TestCase):
         print(expr)
         self.assertEqual("(0-9)", repr(expr))
 
+    def testEmptyExpressionsAreHandledProperly(self):
+        from pyparsing.diagram import to_railroad
+        for cls in (pp.And, pp.Or, pp.MatchFirst, pp.Each):
+            print("testing empty", cls.__name__)
+            expr = cls([])
+            expr.streamline()
+            to_railroad(expr)
+
 
 class Test03_EnablePackratParsing(TestCase):
     def runTest(self):