Added coverage report to tests

requirements-tests.txt

 -r requirements.txt
 pytest==3.4.2
+pytest-cov==2.6.0
 mock==2.0.0
 flake8==3.5.0

setup.cfg

@@ -7,3 +7,6 @@ universal = 1
 [upload]
 sign=true
 identity=0x1784577F811F6EAC
+
+[tool:pytest]
+addopts = --cov=sshuttle --cov-branch --cov-report=term-missing

setup.py

@@ -57,6 +57,12 @@ setup(
             'sshuttle = sshuttle.cmdline:main',
         ],
     },
-    tests_require=['pytest', 'pytest-runner', 'mock'],
+    tests_require=[
+        'pytest',
+        'pytest-cov',
+        'pytest-runner',
+        'mock',
+        'flake8',
+    ],
     keywords="ssh vpn",
 )