diff --git a/.coveragerc b/.coveragerc
index 0cd5f9b4..ceee8a6a 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -1,5 +1,7 @@
 [run]
-plugins = Cython.Coverage
-source  = indexed_gzip
-omit    =
+plugins     = Cython.Coverage
+concurrency = thread multiprocessing
+parallel    = True
+source      = indexed_gzip
+omit        =
     indexed_gzip/tests/*