diff --git a/.coveragerc b/.coveragerc
index ac42c38..c77e177 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -5,3 +5,6 @@ omit =
     /*/__init__.py
     /setup.py
     /*/migrations/*
+source = openwisp_ipam
+parallel = true
+concurrency = multiprocessing
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 651b267..0e968b5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -56,9 +56,9 @@ jobs:
 
       - name: Tests
         run: |
-          coverage run --source=openwisp_ipam runtests.py
-          # SAMPLE tests do not influence coverage, so we can speed up tests with --parallel
-          SAMPLE_APP=1 ./runtests.py --parallel --keepdb
+          coverage run ./runtests.py --parallel
+          SAMPLE_APP=1 coverage run ./runtests.py --parallel
+          coverage combine
 
       - name: Upload Coverage
         run: coveralls --service=github