added test for ol start check

Author: AlexVonB

tests/test_lists.py

@@ -43,6 +43,9 @@
 def test_ol():
     assert md('<ol><li>a</li><li>b</li></ol>') == '1. a\n2. b\n'
     assert md('<ol start="3"><li>a</li><li>b</li></ol>') == '3. a\n4. b\n'
+    assert md('<ol start="-1"><li>a</li><li>b</li></ol>') == '1. a\n2. b\n'
+    assert md('<ol start="foo"><li>a</li><li>b</li></ol>') == '1. a\n2. b\n'
+    assert md('<ol start="1.5"><li>a</li><li>b</li></ol>') == '1. a\n2. b\n'
 
 
 def test_nested_ols():