pipe benchmark result to diff directly

Makefile

@@ -57,18 +57,12 @@ PS_BRIDGE_OUTPUT_DIR := agora-purescript-bridge/
 ps_bridge:
 	cabal run exe:agora-purescript-bridge -- -o $(PS_BRIDGE_OUTPUT_DIR)
 
+BENCH_OUTPUT = "bench.csv"
 bench:
-	cabal run agora-bench
+	cabal run agora-bench -- -o $(BENCH_OUTPUT)
 
-BENCH_TMPDIR := $(shell mktemp -d)
-BENCH_TMPFILE := $(BENCH_TMPDIR)/bench.csv
 bench_check:
-	(cabal run agora-bench -- -o "$(BENCH_TMPFILE)" \
-		|| $(bench) -o "$(BENCH_TMPFILE)") >> /dev/null
-	diff bench.csv $(BENCH_TMPFILE) \
-		|| (echo "bench.csv is outdated"; exit 1)
-	# TODO: do the clean-up even if `diff` fails.
-	rm -rf $(BENCH_TMPDIR)
+	cabal -v0 new-run agora-bench | diff bench.csv -
 
 scripts:
 	cabal run agora-scripts -- -c

agora-bench/Main.hs

@@ -3,10 +3,10 @@ module Main (main) where
 import Bench (specificationTreeToBenchmarks)
 import Data.Csv (EncodeOptions (encUseCrLf), defaultEncodeOptions, encodeDefaultOrderedByNameWith)
 import Data.Text.Lazy.Encoding (decodeUtf8)
-import Data.Text.Lazy.IO as I (writeFile)
+import Data.Text.Lazy.IO as I (putStr, writeFile)
 import Options (Options (..), parseOptions)
 import Prettyprinter (defaultLayoutOptions, layoutPretty, pretty)
-import Prettyprinter.Render.String (renderString)
+import Prettyprinter.Render.Text (renderLazy)
 import Spec.AuthorityToken qualified as AuthorityToken
 import Spec.Effect.GovernorMutation qualified as GovernorMutation
 import Spec.Effect.TreasuryWithdrawal qualified as TreasuryWithdrawal
@@ -14,6 +14,7 @@ import Spec.Governor qualified as Governor
 import Spec.Proposal qualified as Proposal
 import Spec.Stake qualified as Stake
 import Spec.Treasury qualified as Treasury
+import System.IO (hIsTerminalDevice, stdout)
 import Test.Specification (group)
 import Prelude
 
@@ -22,11 +23,14 @@ import Prelude
 main :: IO ()
 main = do
   options <- parseOptions
+  isTTY <- hIsTerminalDevice stdout
 
-  I.writeFile options.output $
-    (decodeUtf8 . encodeDefaultOrderedByNameWith encodeOptions) res
+  mapM_ (`I.writeFile` csv) options.output
 
-  mapM_ (putStrLn . renderString . layoutPretty defaultLayoutOptions . pretty) res
+  I.putStr $
+    if isTTY
+      then prettified
+      else csv
   where
     encodeOptions =
       defaultEncodeOptions
@@ -49,3 +53,7 @@ main = do
           , group "AuthorityToken" AuthorityToken.specs
           , group "Governor" Governor.specs
           ]
+
+    csv = decodeUtf8 $ encodeDefaultOrderedByNameWith encodeOptions res
+
+    prettified = renderLazy $ layoutPretty defaultLayoutOptions $ pretty res

agora-bench/Options.hs

@@ -1,21 +1,22 @@
 module Options (Options (..), parseOptions) where
 
+import Control.Applicative (optional)
 import Options.Applicative ((<**>))
 import Options.Applicative qualified as Opt
 
 newtype Options = Options
-  { output :: FilePath
+  { output :: Maybe FilePath
   }
 
-outputOpt :: Opt.Parser FilePath
+outputOpt :: Opt.Parser (Maybe FilePath)
 outputOpt =
-  Opt.strOption
-    ( Opt.long "output-path"
-        <> Opt.short 'o'
-        <> Opt.metavar "OUTPUT_PATH"
-        <> Opt.value "./bench.csv"
-        <> Opt.help "The path of the bench report file."
-    )
+  optional $
+    Opt.strOption
+      ( Opt.long "output-path"
+          <> Opt.short 'o'
+          <> Opt.metavar "OUTPUT_PATH"
+          <> Opt.help "The path of the bench report file."
+      )
 
 benchOpt :: Opt.Parser Options
 benchOpt = Options <$> outputOpt