diff --git a/test/Prelude.purs b/test/Prelude.purs
index 9477ac586..9ef083142 100644
--- a/test/Prelude.purs
+++ b/test/Prelude.purs
@@ -98,15 +98,20 @@ shouldEqualStr
   -> String
   -> m Unit
 shouldEqualStr v1 v2 =
+  let
+    renderNonPrinting =
+      String.replaceAll (String.Pattern "\r") (String.Replacement "␍")
+      >>> String.replaceAll (String.Pattern "\t") (String.Replacement "␉-->")
+  in
   when (v1 /= v2) do
     fail $ Array.intercalate "\n"
       [ ""
       , "===== (Actual)"
-      , v1
+      , renderNonPrinting v1
       , "====="
       , "  ≠"
       , "===== (Expected)"
-      , v2
+      , renderNonPrinting v2
       , "====="
       , ""
       ]
diff --git a/test/Spago/Build.purs b/test/Spago/Build.purs
index bfbe4c258..9d91e68c0 100644
--- a/test/Spago/Build.purs
+++ b/test/Spago/Build.purs
@@ -39,9 +39,10 @@ spec = Spec.around withTempDir do
           { stdoutFile: Nothing
           , stderrFile: Just (fixture "purs-not-ok.txt")
           , result: isLeft
-          , sanitize: String.trim
-              >>> String.replace (String.Pattern "Usage: purs.bin") (String.Replacement "Usage: purs")
-              >>> String.replace (String.Pattern "\r\n") (String.Replacement "\n")
+          , sanitize:
+              String.trim
+              >>> String.replaceAll (String.Pattern "Usage: purs.bin") (String.Replacement "Usage: purs")
+              >>> String.replaceAll (String.Pattern "\r\n") (String.Replacement "\n")
           }
 
     Spec.it "passes options to purs" \{ spago } -> do