Remove polyfill for assertRaisesRegex function in unittest module (#123)

No longer needed since Python 2 support has been dropped

nrrd/tests/test_formatting.py

@@ -1,7 +1,8 @@
+import unittest
+
 import numpy as np
 
 import nrrd
-from nrrd.tests.util import *
 
 
 class TestFieldFormatting(unittest.TestCase):

nrrd/tests/test_parsing.py

@@ -1,7 +1,8 @@
+import unittest
+
 import numpy as np
 
 import nrrd
-from nrrd.tests.util import *
 
 
 class TestFieldParsing(unittest.TestCase):

nrrd/tests/test_reading.py

@@ -1,3 +1,5 @@
+import unittest
+
 import numpy as np
 
 import nrrd

nrrd/tests/test_writing.py

@@ -1,5 +1,6 @@
 import io
 import tempfile
+import unittest
 
 import numpy as np
 

nrrd/tests/util.py

@@ -1,5 +1,4 @@
 import os
-import unittest
 import warnings
 
 # Enable all warnings
@@ -22,8 +21,3 @@
 ASCII_1D_NRRD_FILE_PATH = os.path.join(DATA_DIR_PATH, 'test1d_ascii.nrrd')
 ASCII_2D_NRRD_FILE_PATH = os.path.join(DATA_DIR_PATH, 'test2d_ascii.nrrd')
 ASCII_1D_CUSTOM_FIELDS_FILE_PATH = os.path.join(DATA_DIR_PATH, 'test_customFields.nrrd')
-
-# Fix issue with assertRaisesRegex only available in Python 3 while
-# assertRaisesRegexp is available in Python 2 (and deprecated in Python 3)
-if not hasattr(unittest.TestCase, 'assertRaisesRegex'):
-    unittest.TestCase.assertRaisesRegex = getattr(unittest.TestCase, 'assertRaisesRegexp')