Merge ~ballot/charm-mongodb/+git/charm-mongodb:pytest into charm-mongodb:master

[Benjamin Allot]

Use pytest instead of unittests

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

diff --git a/tests/unit/requirements.txt b/tests/unit/requirements.txt
index 55e3ba6..9fab1de 100644
--- a/tests/unit/requirements.txt
+++ b/tests/unit/requirements.txt
@@ -6,4 +6,6 @@ charm-tools
 packaging
 appdirs
 pymongo
+pytest
+pytest-cov
 PyYAML
diff --git a/tox.ini b/tox.ini
index 6a2caf4..089508c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -67,10 +67,11 @@ deps =
     black
 
 [testenv:unit]
+setenv =
+    PYTHONPATH = {toxinidir}/tests/unit:{toxinidir}/files/nrpe-external-master
 commands =
-    coverage run -m unittest discover -s {toxinidir}/tests/unit -v
-    coverage report --omit tests/*,mod/*,.tox/*,charmhelpers/*
-    coverage html --omit tests/*,mod/*,.tox/*,charmhelpers/*
+    pytest \
+      {posargs:-v  --cov=hooks --cov-report=term-missing --cov-branch} {toxinidir}/tests/unit
 deps = -r{toxinidir}/tests/unit/requirements.txt
 
 [testenv:func]