package-tests helper cabal_install_with_docs for building with docs.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Cabal/tests/PackageTests/PackageTester.hs

@@ -28,6 +28,7 @@ module PackageTests.PackageTester
     , cabal'
     , cabal_build
     , cabal_install
+    , cabal_install_with_docs
     , ghcPkg
     , ghcPkg'
     , compileSetup
@@ -421,6 +422,17 @@ cabal_install args = do
     cabal "register" []
     return ()
 
+-- | This abstracts the common pattern of "installing" a package,
+-- with haddock documentation.
+cabal_install_with_docs :: [String] -> TestM ()
+cabal_install_with_docs args = do
+    cabal "configure" args
+    cabal "build" []
+    cabal "haddock" []
+    cabal "copy" []
+    cabal "register" []
+    return ()
+
 -- | Determines what Setup executable to run and runs it
 doCabal :: [String]  -- ^ extra arguments
       -> TestM Result