diff --git a/IPython/core/tests/test_magic_terminal.py b/IPython/core/tests/test_magic_terminal.py
index cffb767..d798428 100644
--- a/IPython/core/tests/test_magic_terminal.py
+++ b/IPython/core/tests/test_magic_terminal.py
@@ -21,9 +21,6 @@ def check_cpaste(code, should_fail=False):
     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)