add file/mmap test cases

Author: jorisvandenbossche

pandas/io/tests/parser/common.py

@@ -1605,6 +1605,18 @@ def test_internal_eof_byte(self):
 
     def test_file_handles(self):
         # GH 14418 - don't close user provided file handles
+
         fh = StringIO('a,b\n1,2')
         self.read_csv(fh)
         self.assertFalse(fh.closed)
+
+        with open(self.csv1, 'r') as f:
+            self.read_csv(f)
+            self.assertFalse(f.closed)
+
+        import mmap
+        with open(self.csv1, 'r') as f:
+            m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+            self.read_csv(m)
+            self.assertFalse(m.closed)
+            m.close()