Use proper xunit format for some test.

In particular we now can use proper methods to check that some warnings
are raised instead of making sure the test is printed. As pytest
captures warning by default this add compatibility with pytest.

IPython/utils/tests/test_io.py

@@ -66,21 +66,24 b' def test_io_init():'
         # just test for string equality.
         assert 'IPython.utils.io.IOStream' in classname, classname
 
-def test_IOStream_init():
+class TestIOStream(unittest.TestCase):
+
+    def test_IOStream_init(self):
     """IOStream initializes from a file-like object missing attributes. """
     # Cause a failure from getattr and dir(). (Issue #6386)
     class BadStringIO(StringIO):
         def __dir__(self):
-            attrs = super(StringIO, self).__dir__()
+                attrs = super().__dir__()
             attrs.append('name')
             return attrs
-
+        with self.assertWarns(DeprecationWarning):
     iostream = IOStream(BadStringIO())
     iostream.write('hi, bad iostream\n')
+
     assert not hasattr(iostream, 'name')
     iostream.close()
 
-def test_capture_output():
+    def test_capture_output(self):
     """capture_output() context works"""
     
     with capture_output() as io:
@@ -89,5 +92,3 b' def test_capture_output():'
     
     nt.assert_equal(io.stdout, 'hi, stdout\n')
     nt.assert_equal(io.stderr, 'hi, stderr\n')
-
-

IPython/utils/tests/test_path.py

@@ -263,9 +263,12 b' def test_get_long_path_name():'
     p = path.get_long_path_name('/usr/local')
     nt.assert_equal(p,'/usr/local')
 
+
+class TestRaiseDeprecation(unittest.TestCase):
+
 @dec.skip_win32 # can't create not-user-writable dir on win
 @with_environment
-def test_not_writable_ipdir():
+    def test_not_writable_ipdir(self):
     tmpdir = tempfile.mkdtemp()
     os.name = "posix"
     env.pop('IPYTHON_DIR', None)
@@ -282,7 +285,7 b' def test_not_writable_ipdir():'
         # I can still write to an unwritable dir,
         # assume I'm root and skip the test
         raise SkipTest("I can't create directories that I can't write to")
-    with AssertPrints('is not a writable location', channel='stderr'):
+        with self.assertWarnsRegex(UserWarning, 'is not a writable location'):
         ipdir = paths.get_ipython_dir()
     env.pop('IPYTHON_DIR', None)
 
@@ -313,7 +316,7 b' def test_unicode_in_filename():'
     """
     try:
         # these calls should not throw unicode encode exceptions
-        path.get_py_filename('fooéè.py', force_win32=False)
+        path.get_py_filename('fooéè.py')
     except IOError as ex:
         str(ex)
 
@@ -406,7 +409,7 b' def test_ensure_dir_exists():'
         with nt.assert_raises(IOError):
             path.ensure_dir_exists(f)
 
-class TestLinkOrCopy(object):
+class TestLinkOrCopy(unittest.TestCase):
     def setUp(self):
         self.tempdir = TemporaryDirectory()
         self.src = self.dst("src")