lib: search all .hs files for doctests

hledger-lib/hledger-lib.cabal

@@ -188,5 +188,7 @@ test-suite doctests
   main-is: doctests.hs
   build-depends:
       base
+    , Glob >= 0.7
     , doctest >= 0.8
+    --, hledger-lib ?
   default-language: Haskell2010

hledger-lib/tests/doctests.hs

@@ -1,6 +1,9 @@
+{-# LANGUAGE PackageImports #-}
+
+import Data.List
+import "Glob" System.FilePath.Glob
 import Test.DocTest
 
-main = doctest [
-   "Hledger/Read/JournalReader.hs"
-  ,"Hledger/Data/Dates.hs"
-  ]
+main = do
+  fs <- ("Hledger.hs" :) . filter (not . isInfixOf "/.") <$> glob "Hledger/**/*.hs"
+  doctest fs