From 32eff19bb60215ff2723f1ee2d9bfa2874f9ea75 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kamil=20Ga=C5=82uszka?= <kamil.galuszka@solution4future.com>
Date: Thu, 15 Oct 2020 01:05:40 +0200
Subject: [PATCH] fix: linter fixes and added python 3.9 to tests

---
 .travis.yml              | 2 +-
 libagent/server.py       | 4 ++--
 libagent/ssh/protocol.py | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index dfa6344..3f8b32d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,10 @@
 sudo: false
 language: python
 python:
-  - "3.5"
   - "3.6"
   - "3.7"
   - "3.8"
+  - "3.9"
 
 cache:
   directories:
diff --git a/libagent/server.py b/libagent/server.py
index 7d517fc..4dc48af 100644
--- a/libagent/server.py
+++ b/libagent/server.py
@@ -158,8 +158,8 @@ def run_process(command, environ):
     env.update(environ)
     try:
         p = subprocess.Popen(args=command, env=env)
-    except OSError as e:
-        raise OSError('cannot run %r: %s' % (command, e))
+    except OSError as exc:
+        raise OSError('cannot run %r: %s' % (command, exc)) from exc
     log.debug('subprocess %d is running', p.pid)
     ret = p.wait()
     log.debug('subprocess %d exited: %d', p.pid, ret)
diff --git a/libagent/ssh/protocol.py b/libagent/ssh/protocol.py
index d9c4a2d..f2d9eb5 100644
--- a/libagent/ssh/protocol.py
+++ b/libagent/ssh/protocol.py
@@ -149,9 +149,9 @@ class Handler:
         try:
             sig_bytes = key['verifier'](sig=signature, msg=blob)
             log.info('signature status: OK')
-        except formats.ecdsa.BadSignatureError:
+        except formats.ecdsa.BadSignatureError as exc:
             log.exception('signature status: ERROR')
-            raise ValueError('invalid ECDSA signature')
+            raise ValueError('invalid ECDSA signature') from exc
 
         log.debug('signature size: %d bytes', len(sig_bytes))