Add more tests for delimitercommand.py

test/pytests/test_delimitercommand.py

@@ -55,6 +55,16 @@ def test_queries_iter_with_custom_delimiter_preserves_semicolons_inside_statemen
     ]
 
 
+def test_split_handles_placeholder_collision_in_original_sql() -> None:
+    command = DelimiterCommand()
+    command.set('$$')
+
+    assert command._split('select \ufffc1; select 2$$ select 3$$') == [
+        'select \ufffc1; select 2$$',
+        'select 3$$',
+    ]
+
+
 def test_queries_iter_resplits_remaining_input_after_delimiter_change() -> None:
     command = DelimiterCommand()
     queries = command.queries_iter('select 1; delimiter $$ select 2$$ select 3$$')
@@ -65,3 +75,26 @@ def test_queries_iter_resplits_remaining_input_after_delimiter_change() -> None:
     command.set('$$')
 
     assert list(queries) == ['select 2', 'select 3']
+
+
+def test_queries_iter_reappends_old_trailing_delimiter_before_resplitting(monkeypatch) -> None:
+    command = DelimiterCommand()
+    command._delimiter = ';;'
+    split_calls: list[str] = []
+
+    def fake_split(sql: str) -> list[str]:
+        split_calls.append(sql)
+        if len(split_calls) == 1:
+            return ['delimiter $$;;', 'select 2$$']
+        return ['ignored', 'select 2']
+
+    monkeypatch.setattr(command, '_split', fake_split)
+
+    queries = command.queries_iter('ignored')
+
+    assert next(queries) == 'delimiter $$'
+
+    command.set('$$')
+
+    assert list(queries) == ['select 2']
+    assert split_calls == ['ignored', 'delimiter $$ select 2$$;;']