diff --git a/Makefile b/Makefile
index fe935dea1..c482d367d 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ test_coverage: build/covimerage build/vader | build
 
 build/covimerage:
 	virtualenv $@
-	. $@/bin/activate && pip install https://github.com/Vimjas/covimerage/archive/develop.zip
+	. $@/bin/activate && pip install --no-cache-dir https://github.com/Vimjas/covimerage/archive/develop.zip
 
 build/vader:
 	git clone --depth 1 https://github.com/junegunn/vader.vim.git $@