diff --git a/Lib/test/test_tools.py b/Lib/test/test_tools.py
--- a/Lib/test/test_tools.py
+++ b/Lib/test/test_tools.py
@@ -35,16 +35,42 @@ class ReindentTests(unittest.TestCase):
         assert_python_ok(self.script)
 
     def test_help(self):
         rc, out, err = assert_python_ok(self.script, '-h')
         self.assertEqual(out, b'')
         self.assertGreater(err, b'')
 
 
+class Md5sumTests(unittest.TestCase):
+    script = os.path.join(scriptsdir, 'md5sum.py')
+
+    def test_md5sum(self):
+        rc, out, err = assert_python_ok(self.script, self.script)
+        self.assertEqual(rc, 0)
+        self.assertIn(self.script.encode('ascii'), out)
+        self.assertEqual(err, b'')
+
+    def test_md5sum_multiple_files(self):
+        rc, out, err = assert_python_ok(self.script, self.script,
+                                        ReindentTests.script)
+        self.assertEqual(rc, 0)
+        self.assertEqual(len(out.splitlines()), 2)
+        self.assertIn(self.script.encode('ascii'), out)
+        self.assertIn(ReindentTests.script.encode('ascii'), out)
+        self.assertEqual(err, b'')
+
+    def test_md5sum_l_option(self):
+        rc, out, err = assert_python_ok(self.script, '-l', self.script)
+        self.assertEqual(rc, 0)
+        self.assertNotIn(self.script.encode('ascii'), out)
+        self.assertIn(os.path.basename(self.script).encode('ascii'), out)
+        self.assertEqual(err, b'')
+
+
 class PindentTests(unittest.TestCase):
     script = os.path.join(scriptsdir, 'pindent.py')
 
     def assertFileEqual(self, fn1, fn2):
         with open(fn1) as f1, open(fn2) as f2:
             self.assertEqual(f1.readlines(), f2.readlines())
 
     def pindent(self, source, *args):
diff --git a/Tools/scripts/md5sum.py b/Tools/scripts/md5sum.py
--- a/Tools/scripts/md5sum.py
+++ b/Tools/scripts/md5sum.py
@@ -12,24 +12,25 @@ usage = """
 usage: sum5 [-b] [-t] [-l] [-s bufsize] [file ...]
 -b        : read files in binary mode (default)
 -t        : read files in text mode (you almost certainly don't want this!)
 -l        : print last pathname component only
 -s bufsize: read buffer size (default %d)
 file ...  : files to sum; '-' or no files means stdin
 """ % bufsize
 
+import io
 import sys
 import os
 import getopt
 from hashlib import md5
 
 def sum(*files):
     sts = 0
-    if files and isinstance(files[-1], file):
+    if files and isinstance(files[-1], io.IOBase):
         out, files = files[-1], files[:-1]
     else:
         out = sys.stdout
     if len(files) == 1 and not isinstance(files[0], str):
         files = files[0]
     for f in files:
         if isinstance(f, str):
             if f == '-':
@@ -48,17 +49,17 @@ def printsum(filename, out=sys.stdout):
         return 1
     if fnfilter:
         filename = fnfilter(filename)
     sts = printsumfp(fp, filename, out)
     fp.close()
     return sts
 
 def printsumfp(fp, filename, out=sys.stdout):
-    m = md5.new()
+    m = md5()
     try:
         while 1:
             data = fp.read(bufsize)
             if not data:
                 break
             m.update(data)
     except IOError as msg:
         sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))