conway governance hash: add test that stdout and --out-file yield the…

… same result

cardano-cli/cardano-cli.cabal

@@ -317,6 +317,7 @@ test-suite cardano-cli-test
 
   other-modules:        Test.Cli.CliIntermediateFormat
                         Test.Cli.FilePermissions
+                        Test.Cli.Governance.Hash
                         Test.Cli.ITN
                         Test.Cli.JSON
                         Test.Cli.Pioneers.Exercise1

cardano-cli/test/cardano-cli-test/Test/Cli/Governance/Hash.hs

@@ -0,0 +1,42 @@
+{- HLINT ignore "Use camelCase" -}
+
+module Test.Cli.Governance.Hash where
+
+import           Control.Monad (void)
+
+import           Test.Cardano.CLI.Util
+
+import           Hedgehog (Property)
+import qualified Hedgehog as H
+import qualified Hedgehog.Extras as H
+
+hprop_governance_hash_trip :: Property
+hprop_governance_hash_trip =
+  propertyOnce $ do
+    governance_hash_trip_fun "foo"
+    governance_hash_trip_fun "longerText"
+    governance_hash_trip_fun "nonAscii: 你好"
+    governance_hash_trip_fun "nonAscii: à la mode de Cæn"
+
+-- Test that @cardano-cli conway governance hash --text > file1@ and
+-- @cardano-cli conway governance hash --text --out-file file2@ yields
+-- similar @file1@ and @file2@ files.
+governance_hash_trip_fun :: String -> H.PropertyT IO ()
+governance_hash_trip_fun input =
+  H.moduleWorkspace "tmp" $ \tempDir -> do
+    hashFile <- noteTempFile tempDir "hash.txt"
+
+    hash <- execCardanoCLI
+      [ "conway", "governance", "hash"
+        , "--text", input
+      ]
+
+    void $ execCardanoCLI
+      [ "conway", "governance", "hash"
+      , "--text", input
+      , "--out-file", hashFile
+      ]
+
+    hashFromFile <- H.readFile hashFile
+
+    H.diff hash (==) hashFromFile