diff --git a/ghc-mod.cabal b/ghc-mod.cabal
index 1e44aa9..d3216ee 100644
--- a/ghc-mod.cabal
+++ b/ghc-mod.cabal
@@ -142,6 +142,7 @@ Test-Suite spec
                         GhcPkgSpec
   Build-Depends:        base >= 4.0 && < 5
                       , containers
+                      , deepseq
                       , directory
                       , filepath
                       , ghc