Test (and fix) new D209

Add failing test for new D209 and fixed the logic.

Author: ziadsawalha

pep257.py

@@ -609,9 +609,7 @@ def check_newline_after_last_paragraph(self, definition, docstring):
         if docstring:
             lines = [l for l in eval(docstring).split('\n') if not is_blank(l)]
             if len(lines) > 1:
-                lines = eval(docstring).split('\n')
-                blanks = len(list(takewhile(is_blank, reversed(lines))))
-                if blanks < 2:
+                if docstring.split("\n")[-1].strip() not in ['"""', "'''"]:
                     return Error('D209: Put multi-line docstring closing '
                                  'quotes on separate line')
 

test.py

@@ -201,6 +201,22 @@ def foobar():
     """Signature: foobar()."""
 
 
+def new_209():
+    """First line.
+
+    More lines.
+    """
+    pass
+
+
+def old_209():
+    """One liner.
+
+    Multi-line comments. OK to have extra blank line
+
+    """
+
+
 def run():
     """Run the functions above and check errors agains expected errors."""
     import pep257