added pytest-cov to check test coverage

requirements.txt

@@ -48,9 +48,13 @@ lazy-object-proxy==1.4.3
 Mako==1.1.2
 MarkupSafe==1.1.1
 mccabe==0.6.1
+more-itertools==8.4.0
+packaging==20.4
 paramiko==2.7.1
 pathspec==0.8.0
+pluggy==0.13.1
 psycopg2-binary==2.8.3
+py==1.8.2
 pycodestyle==2.6.0
 pycparser==2.18
 pyflakes==2.2.0
@@ -60,7 +64,10 @@ pylint-flask==0.6
 pylint-plugin-utils==0.6
 PyMySQL==0.9.2
 PyNaCl==1.3.0
+pyparsing==2.4.7
 pyrsistent==0.16.0
+pytest==5.4.3
+pytest-cov==2.10.0
 python-dateutil==2.7.3
 python-dotenv==0.8.2
 python-editor==1.0.4