Fix some tests.

Author: serhiy-storchaka

Lib/test/test_frame.py

@@ -253,7 +253,7 @@ def __del__(self):
             def gen():
                 yield
 
-            fd = open({__file__!r})
+            fd = open({__file__!r}, 'rb')
             l = [fd, GCHello()]
             l.append(l)
             del fd

Lib/test/test_mailcap.py

@@ -93,7 +93,7 @@ def test_listmailcapfiles(self):
 
     def test_readmailcapfile(self):
         # Test readmailcapfile() using test file. It should match MAILCAPDICT.
-        with open(MAILCAPFILE, 'r') as mcf:
+        with open(MAILCAPFILE, 'r', encoding='utf-8') as mcf:
             with self.assertWarns(DeprecationWarning):
                 d = mailcap.readmailcapfile(mcf)
         self.assertDictEqual(d, MAILCAPDICT_DEPRECATED)

Lib/test/test_xml_etree.py

@@ -3717,10 +3717,6 @@ def test_write_to_filename_with_encoding(self):
 
     def test_write_to_filename_as_unicode(self):
         self.addCleanup(os_helper.unlink, TESTFN)
-        with open(TESTFN, 'w') as f:
-            encoding = f.encoding
-        os_helper.unlink(TESTFN)
-
         tree = ET.ElementTree(ET.XML('''<site>\xf8</site>'''))
         tree.write(TESTFN, encoding='unicode')
         with open(TESTFN, 'rb') as f: