diff --git a/requirements-dev.txt b/requirements-dev.txt
index 3e29aca..a16a31a 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,6 +1,7 @@
 # matplotlib
 # numpy
 pexpect
+coverage==4.2
 pytest==3.0.5
 pytest-cov==2.4.0
 python-coveralls