Add test cases to cabal file

s-cargot.cabal

@@ -19,7 +19,9 @@ category:            Data
 build-type:          Simple
 cabal-version:       >=1.10
 bug-reports:         https://github.com/aisamanra/s-cargot/issues
-extra-source-files:  README.md, CHANGELOG.md
+extra-source-files:  README.md,
+                     CHANGELOG.md,
+                     test/*.sexp
 
 source-repository head
   type: git