Split kind tests into component-owned probes

test/Nuthatch/Probe/Assert.hs

@@ -0,0 +1,27 @@
+module Nuthatch.Probe.Assert
+  ( assert
+  , assertContains
+  , assertEqual
+  , requireEnv
+  ) where
+
+import           Control.Monad (unless)
+import qualified Data.ByteString as BS
+import           System.Environment (lookupEnv)
+
+assert :: String -> Bool -> IO ()
+assert label condition =
+  unless condition (fail label)
+
+assertContains :: String -> BS.ByteString -> BS.ByteString -> IO ()
+assertContains label needle haystack =
+  assert label (needle `BS.isInfixOf` haystack)
+
+assertEqual :: (Eq value, Show value) => String -> value -> value -> IO ()
+assertEqual label expected actual =
+  unless (actual == expected) $
+    fail (label <> ": expected " <> show expected <> ", got " <> show actual)
+
+requireEnv :: String -> IO String
+requireEnv name =
+  lookupEnv name >>= maybe (fail ("missing " <> name)) pure