diff --git a/src/testdir/test86.in b/src/testdir/test86.in
index 819ae95..32888f8 100644
--- a/src/testdir/test86.in
+++ b/src/testdir/test86.in
@@ -1094,8 +1094,20 @@
 ee('del sys.stdout.softspace')
 number_test('sys.stdout.softspace = %s', unsigned=True)
 number_test('sys.stderr.softspace = %s', unsigned=True)
+ee('assert sys.stdout.isatty()==False')
+ee('assert sys.stdout.seekable()==False')
+ee('sys.stdout.close()')
+ee('sys.stdout.flush()')
+ee('assert sys.stderr.isatty()==False')
+ee('assert sys.stderr.seekable()==False')
+ee('sys.stderr.close()')
+ee('sys.stderr.flush()')
 ee('sys.stdout.attr = None')
 cb.append(">> OutputWrite")
+ee('assert sys.stdout.writable()==True')
+ee('assert sys.stdout.readable()==False')
+ee('assert sys.stderr.writable()==True')
+ee('assert sys.stderr.readable()==False')
 ee('sys.stdout.write(None)')
 cb.append(">> OutputWriteLines")
 ee('sys.stdout.writelines(None)')
diff --git a/src/testdir/test86.ok b/src/testdir/test86.ok
index 8edb749..5cb0ac5 100644
--- a/src/testdir/test86.ok
+++ b/src/testdir/test86.ok
@@ -447,7 +447,7 @@
 dictionary:__dir__,__members__,get,has_key,items,keys,locked,pop,popitem,scope,update,values
 list:__dir__,__members__,extend,locked
 function:__dir__,__members__,softspace
-output:__dir__,__members__,flush,softspace,write,writelines
+output:__dir__,__members__,close,flush,isatty,readable,seekable,softspace,writable,write,writelines
 {}
 {'a': 1}
 {'a': 1}
@@ -488,8 +488,20 @@
 sys.stderr.softspace = None:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
 sys.stderr.softspace = -1:ValueError:('number must be greater or equal to zero',)
 <<< Finished
+assert sys.stdout.isatty()==False:NOT FAILED
+assert sys.stdout.seekable()==False:NOT FAILED
+sys.stdout.close():NOT FAILED
+sys.stdout.flush():NOT FAILED
+assert sys.stderr.isatty()==False:NOT FAILED
+assert sys.stderr.seekable()==False:NOT FAILED
+sys.stderr.close():NOT FAILED
+sys.stderr.flush():NOT FAILED
 sys.stdout.attr = None:AttributeError:('invalid attribute: attr',)
 >> OutputWrite
+assert sys.stdout.writable()==True:NOT FAILED
+assert sys.stdout.readable()==False:NOT FAILED
+assert sys.stderr.writable()==True:NOT FAILED
+assert sys.stderr.readable()==False:NOT FAILED
 sys.stdout.write(None):TypeError:('coercing to Unicode: need string or buffer, NoneType found',)
 >> OutputWriteLines
 sys.stdout.writelines(None):TypeError:("'NoneType' object is not iterable",)
diff --git a/src/testdir/test87.in b/src/testdir/test87.in
index e24df41..fedc795 100644
--- a/src/testdir/test87.in
+++ b/src/testdir/test87.in
@@ -1071,8 +1071,20 @@
 ee('del sys.stdout.softspace')
 number_test('sys.stdout.softspace = %s', unsigned=True)
 number_test('sys.stderr.softspace = %s', unsigned=True)
+ee('assert sys.stdout.isatty()==False')
+ee('assert sys.stdout.seekable()==False')
+ee('sys.stdout.close()')
+ee('sys.stdout.flush()')
+ee('assert sys.stderr.isatty()==False')
+ee('assert sys.stderr.seekable()==False')
+ee('sys.stderr.close()')
+ee('sys.stderr.flush()')
 ee('sys.stdout.attr = None')
 cb.append(">> OutputWrite")
+ee('assert sys.stdout.writable()==True')
+ee('assert sys.stdout.readable()==False')
+ee('assert sys.stderr.writable()==True')
+ee('assert sys.stderr.readable()==False')
 ee('sys.stdout.write(None)')
 cb.append(">> OutputWriteLines")
 ee('sys.stdout.writelines(None)')
diff --git a/src/testdir/test87.ok b/src/testdir/test87.ok
index e616544..7771733 100644
--- a/src/testdir/test87.ok
+++ b/src/testdir/test87.ok
@@ -447,7 +447,7 @@
 dictionary:__dir__,get,has_key,items,keys,locked,pop,popitem,scope,update,values
 list:__dir__,extend,locked
 function:__dir__,softspace
-output:__dir__,flush,softspace,write,writelines
+output:__dir__,close,flush,isatty,readable,seekable,softspace,writable,write,writelines
 {}
 {'a': 1}
 {'a': 1}
@@ -488,8 +488,20 @@
 sys.stderr.softspace = None:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
 sys.stderr.softspace = -1:(<class 'ValueError'>, ValueError('number must be greater or equal to zero',))
 <<< Finished
+assert sys.stdout.isatty()==False:NOT FAILED
+assert sys.stdout.seekable()==False:NOT FAILED
+sys.stdout.close():NOT FAILED
+sys.stdout.flush():NOT FAILED
+assert sys.stderr.isatty()==False:NOT FAILED
+assert sys.stderr.seekable()==False:NOT FAILED
+sys.stderr.close():NOT FAILED
+sys.stderr.flush():NOT FAILED
 sys.stdout.attr = None:(<class 'AttributeError'>, AttributeError('invalid attribute: attr',))
 >> OutputWrite
+assert sys.stdout.writable()==True:NOT FAILED
+assert sys.stdout.readable()==False:NOT FAILED
+assert sys.stderr.writable()==True:NOT FAILED
+assert sys.stderr.readable()==False:NOT FAILED
 sys.stdout.write(None):(<class 'TypeError'>, TypeError("Can't convert 'NoneType' object to str implicitly",))
 >> OutputWriteLines
 sys.stdout.writelines(None):(<class 'TypeError'>, TypeError("'NoneType' object is not iterable",))