Drop support for Python version below 3.8

.travis.yml

@@ -2,18 +2,12 @@ dist: xenial
 language: python
 
 python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  - "3.7"
   - "3.8"
   - "3.9"
 
 install:
   - pip install -r requirements.txt
-  - pip install 'pytest>=4.6' pytest-cov codecov flake8
-  - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then pip install mock; fi
+  - pip install pytest pytest-cov codecov flake8
 
 script:
   - pytest --cov=webssh

requirements.txt

@@ -1,3 +1,2 @@
-paramiko==2.10.4
-tornado==5.1.1; python_version < '3.5'
-tornado==6.1.0; python_version >= '3.5'
+paramiko==3.0.0
+tornado==6.2.0

tests/sshserver.py

@@ -1,3 +1,4 @@
+import base64
 import random
 import socket
 # import sys
@@ -6,7 +7,6 @@ import threading
 import paramiko
 
 from binascii import hexlify
-from paramiko.py3compat import u, decodebytes
 from tests.utils import make_tests_data_path
 
 
@@ -16,7 +16,7 @@ paramiko.util.log_to_file(make_tests_data_path('sshserver.log'))
 host_key = paramiko.RSAKey(filename=make_tests_data_path('test_rsa.key'))
 # host_key = paramiko.DSSKey(filename='test_dss.key')
 
-print('Read key: ' + u(hexlify(host_key.get_fingerprint())))
+print('Read key: ' + hexlify(host_key.get_fingerprint()).decode('utf-8'))
 
 banner = u'\r\n\u6b22\u8fce\r\n'
 event_timeout = 5
@@ -29,7 +29,7 @@ class Server(paramiko.ServerInterface):
             b'fAu7jJ2d7eothvfeuoRFtJwhUmZDluRdFyhFY/hFAh76PJKGAusIqIQKlkJxMC'
             b'KDqIexkgHAfID/6mqvmnSJf0b5W8v5h2pI/stOSwTQ+pxVhwJ9ctYDhRSlF0iT'
             b'UWT10hcuO4Ks8=')
-    good_pub_key = paramiko.RSAKey(data=decodebytes(data))
+    good_pub_key = paramiko.RSAKey(data=base64.decodebytes(data))
 
     commands = [
         b'$SHELL -ilc "locale charmap"',
@@ -62,7 +62,7 @@ class Server(paramiko.ServerInterface):
         return paramiko.AUTH_FAILED
 
     def check_auth_publickey(self, username, key):
-        print('Auth attempt with username: {!r} & key: {!r}'.format(username, u(hexlify(key.get_fingerprint())))) # noqa
+        print('Auth attempt with username: {!r} & key: {!r}'.format(username, hexlify(key.get_fingerprint()).decode('utf-8'))) # noqa
         if (username in ['robey', 'keyonly']) and (key == self.good_pub_key):
             return paramiko.AUTH_SUCCESSFUL
         if username == 'pkey2fa' and key == self.good_pub_key: