Fix wrongly introduced Python 3 incompatibility. Fixes #14 and #15.

Add static type checks via mypy (optional static type checker),
Add relevant tests, which could trigger the issue.

test/test_errors.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import pytest, socket
+
+
+class TestErrors(object):
+	@pytest.fixture(autouse=True)
+	def init(self, ssh_audit):
+		self.AuditConf = ssh_audit.AuditConf
+		self.audit = ssh_audit.audit
+	
+	def _conf(self):
+		conf = self.AuditConf('localhost', 22)
+		conf.batch = True
+		return conf
+	
+	def test_connection_refused(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.errors['connect'] = socket.error(61, 'Connection refused')
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 1
+		assert 'Connection refused' in lines[-1]
+	
+	def test_connection_closed_before_banner(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(socket.error(54, 'Connection reset by peer'))
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 1
+		assert 'did not receive banner' in lines[-1]
+	
+	def test_connection_closed_after_header(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(b'header line 1\n')
+		vsocket.rdata.append(b'header line 2\n')
+		vsocket.rdata.append(socket.error(54, 'Connection reset by peer'))
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 3
+		assert 'did not receive banner' in lines[-1]
+	
+	def test_connection_closed_after_banner(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(b'SSH-2.0-ssh-audit-test\r\n')
+		vsocket.rdata.append(socket.error(54, 'Connection reset by peer'))
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 2
+		assert 'error reading packet' in lines[-1]
+		assert 'reset by peer' in lines[-1]
+	
+	def test_empty_data_after_banner(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(b'SSH-2.0-ssh-audit-test\r\n')
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 2
+		assert 'error reading packet' in lines[-1]
+		assert 'empty' in lines[-1]
+	
+	def test_wrong_data_after_banner(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(b'SSH-2.0-ssh-audit-test\r\n')
+		vsocket.rdata.append(b'xxx\n')
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			self.audit(self._conf())
+		lines = output_spy.flush()
+		assert len(lines) == 2
+		assert 'error reading packet' in lines[-1]
+		assert 'xxx' in lines[-1]
+	
+	def test_protocol_mismatch_by_conf(self, output_spy, virtual_socket):
+		vsocket = virtual_socket
+		vsocket.rdata.append(b'SSH-1.3-ssh-audit-test\r\n')
+		vsocket.rdata.append(b'Protocol major versions differ.\n')
+		output_spy.begin()
+		with pytest.raises(SystemExit):
+			conf = self._conf()
+			conf.ssh1, conf.ssh2 = True, False
+			self.audit(conf)
+		lines = output_spy.flush()
+		assert len(lines) == 3
+		assert 'error reading packet' in lines[-1]
+		assert 'major versions differ' in lines[-1]