Fix coverage tests to report proper coverage

Change-Id: Ia1d06e5af86f2125abe45300fc5a3c208925ebef
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/tox.ini b/tox.ini
index 1e0b679..582a897 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,11 +17,9 @@
 envlist = cover, flake8, unittest
 
 [testenv]
+usedevelop = True
 basepython = python3
 install_command = python3 -m pip install -r requirements.txt -U {opts} {packages}
-deps = -rtest-requirements.txt
-commands=
-    python3 -m unittest discover -v
 
 [testenv:cover]
 basepython = python3