`io.StringIO` always has `encoding` field

At lease since Python 2.7/3.5+

IPython/core/tests/test_magic_terminal.py

@@ -1,190 +1,187 b''
 """Tests for various magic functions specific to the terminal frontend."""
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import sys
 from io import StringIO
 from unittest import TestCase
 
 from IPython.testing import tools as tt
 
 #-----------------------------------------------------------------------------
 # Test functions begin
 #-----------------------------------------------------------------------------
 
 def check_cpaste(code, should_fail=False):
     """Execute code via 'cpaste' and ensure it was executed, unless
     should_fail is set.
     """
     ip.user_ns['code_ran'] = False
 
     src = StringIO()
-    if not hasattr(src, 'encoding'):
-        # IPython expects stdin to have an encoding attribute
-        src.encoding = None
     src.write(code)
     src.write('\n--\n')
     src.seek(0)
 
     stdin_save = sys.stdin
     sys.stdin = src
 
     try:
         context = tt.AssertPrints if should_fail else tt.AssertNotPrints
         with context("Traceback (most recent call last)"):
                 ip.magic('cpaste')
 
         if not should_fail:
             assert ip.user_ns['code_ran'], "%r failed" % code
     finally:
         sys.stdin = stdin_save
 
 def test_cpaste():
     """Test cpaste magic"""
 
     def runf():
         """Marker function: sets a flag when executed.
         """
         ip.user_ns['code_ran'] = True
         return 'runf' # return string so '+ runf()' doesn't result in success
 
     tests = {'pass': ["runf()",
                       "In [1]: runf()",
                       "In [1]: if 1:\n   ...:     runf()",
                       "> > > runf()",
                       ">>> runf()",
                       "   >>> runf()",
                       ],
 
              'fail': ["1 + runf()",
                       "++ runf()",
              ]}
 
     ip.user_ns['runf'] = runf
 
     for code in tests['pass']:
         check_cpaste(code)
 
     for code in tests['fail']:
         check_cpaste(code, should_fail=True)
 
 
 class PasteTestCase(TestCase):
     """Multiple tests for clipboard pasting"""
 
     def paste(self, txt, flags='-q'):
         """Paste input text, by default in quiet mode"""
         ip.hooks.clipboard_get = lambda : txt
         ip.magic('paste '+flags)
 
     def setUp(self):
         # Inject fake clipboard hook but save original so we can restore it later
         self.original_clip = ip.hooks.clipboard_get
 
     def tearDown(self): 
         # Restore original hook
         ip.hooks.clipboard_get = self.original_clip
        
     def test_paste(self):
         ip.user_ns.pop("x", None)
         self.paste("x = 1")
         self.assertEqual(ip.user_ns["x"], 1)
         ip.user_ns.pop("x")
 
     def test_paste_pyprompt(self):
         ip.user_ns.pop("x", None)
         self.paste(">>> x=2")
         self.assertEqual(ip.user_ns["x"], 2)
         ip.user_ns.pop("x")
 
     def test_paste_py_multi(self):
         self.paste("""
         >>> x = [1,2,3]
         >>> y = []
         >>> for i in x:
         ...     y.append(i**2)
         ... 
         """
         )
         self.assertEqual(ip.user_ns["x"], [1, 2, 3])
         self.assertEqual(ip.user_ns["y"], [1, 4, 9])
 
     def test_paste_py_multi_r(self):
         "Now, test that self.paste -r works"
         self.test_paste_py_multi()
         self.assertEqual(ip.user_ns.pop("x"), [1, 2, 3])
         self.assertEqual(ip.user_ns.pop("y"), [1, 4, 9])
         self.assertFalse("x" in ip.user_ns)
         ip.magic("paste -r")
         self.assertEqual(ip.user_ns["x"], [1, 2, 3])
         self.assertEqual(ip.user_ns["y"], [1, 4, 9])
 
     def test_paste_email(self):
         "Test pasting of email-quoted contents"
         self.paste("""\
         >> def foo(x):
         >>     return x + 1
         >> xx = foo(1.1)"""
         )
         self.assertEqual(ip.user_ns["xx"], 2.1)
 
     def test_paste_email2(self):
         "Email again; some programs add a space also at each quoting level"
         self.paste("""\
         > > def foo(x):
         > >     return x + 1
         > > yy = foo(2.1)     """
         )
         self.assertEqual(ip.user_ns["yy"], 3.1)
 
     def test_paste_email_py(self):
         "Email quoting of interactive input"
         self.paste("""\
         >> >>> def f(x):
         >> ...   return x+1
         >> ... 
         >> >>> zz = f(2.5)      """
         )
         self.assertEqual(ip.user_ns["zz"], 3.5)
 
     def test_paste_echo(self):
         "Also test self.paste echoing, by temporarily faking the writer"
         w = StringIO()
         writer = ip.write
         ip.write = w.write
         code = """
         a = 100
         b = 200"""
         try:
             self.paste(code,'')
             out = w.getvalue()
         finally:
             ip.write = writer
         self.assertEqual(ip.user_ns["a"], 100)
         self.assertEqual(ip.user_ns["b"], 200)
         assert out == code + "\n## -- End pasted text --\n"
 
     def test_paste_leading_commas(self):
         "Test multiline strings with leading commas"
         tm = ip.magics_manager.registry['TerminalMagics']
         s = '''\
 a = """
 ,1,2,3
 """'''
         ip.user_ns.pop("foo", None)
         tm.store_or_execute(s, "foo")
         self.assertIn("foo", ip.user_ns)
 
     def test_paste_trailing_question(self):
         "Test pasting sources with trailing question marks"
         tm = ip.magics_manager.registry['TerminalMagics']
         s = '''\
 def funcfoo():
    if True: #am i true?
        return 'fooresult'
 '''
         ip.user_ns.pop('funcfoo', None)
         self.paste(s)
         self.assertEqual(ip.user_ns["funcfoo"](), "fooresult")