Main version of Python is updated up to 3.7

And small style fixes

.travis.yml

@@ -1,6 +1,6 @@
 language: python
 python:
-  - "2.7"
+  - "3.7"
 install:
   - python setup.py develop
 script:

README.rst

@@ -10,6 +10,8 @@ But uses `requests` instead of `PyCURL`
 
 Release Notes
 =============
+**Version 0.13 – TBD**
+ * Main version of Python is updated up to 3.7
 
 **Version 0.12 - 21.06.2019**
  * Added depth argument in copy method in client.py by https://github.com/JesperHakansson

setup.py

@@ -49,7 +49,8 @@ setup(
     requires=['python (>= 2.7.6)'],
     install_requires=['requests', 'lxml', 'argcomplete'],
     scripts=['wdc'],
-    tests_require=['pytest', 'pyhamcrest', 'junit-xml', 'pytest-allure-adaptor'],
+    test_suite='tests',
+    tests_require=['pytest'],
     cmdclass={'install': Install, 'test': Test},
     description='WebDAV client, based on original package https://github.com/designerror/webdav-client-python but '
                 'uses requests instead of PyCURL',
@@ -73,6 +74,9 @@ setup(
         'Programming Language :: Python :: 3.2',
         'Programming Language :: Python :: 3.3',
         'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Topic :: Internet',
         'Topic :: Software Development :: Libraries :: Python Modules',
     ],

tests/test_client_unit.py

@@ -175,10 +175,10 @@ class ClientTestCase(TestCase):
                   '</d:response></d:multistatus>'
         path = '/test_dir'
         hostname = 'https://webdav.yandex.ru'
-        result = utils.parse_is_dir_response(content.encode('utf-8'), path, hostname)
+        result = utils.parse_is_dir_response(content, path, hostname)
         self.assertTrue(result, 'It should be directory')
 
-    def test_parse_is_dir_response_directory(self):
+    def test_parse_is_dir_response_file(self):
         content = '<?xml version=\'1.0\' encoding=\'UTF-8\'?><d:multistatus xmlns:d="DAV:"><d:response><d:href>/test_' \
                   'dir/</d:href><d:propstat><d:status>HTTP/1.1 200 OK</d:status><d:prop><d:creationdate>2018-05-10T07' \
                   ':40:11Z</d:creationdate><d:displayname>test_dir</d:displayname><d:getlastmodified>Thu, 10 May 2018' \