diff --git a/exercises/practice/etl/EtlTest.lean b/exercises/practice/etl/EtlTest.lean
index b38fd07..a2d04b5 100644
--- a/exercises/practice/etl/EtlTest.lean
+++ b/exercises/practice/etl/EtlTest.lean
@@ -3,31 +3,78 @@ import Etl
 import Std
 
 open LeanTest
-open Std
 
-instance : BEq (HashMap Char Nat) where
-  beq h1 h2 :=
-    h1.size == h2.size &&
-    h1.fold (fun acc k v =>
-      acc && match h2.get? k with
-      | some v' => v == v'
-      | none    => false
-    ) true
+def Std.HashMap.toSortedList (map : Std.HashMap Char Nat) :=
+  map.toArray.qsort (λ (k1, _) (k2, _) => k1 ≤ k2)
+
+instance : BEq (Std.HashMap Char Nat) where
+  beq a b := a.toSortedList == b.toSortedList
 
 def etlTests : TestSuite :=
   (TestSuite.empty "Etl")
   |>.addTest "single letter" (do
-      return assertEqual (.ofList [('a', 1)])
-          (Etl.transform (.ofList [(1, ['A'])])))
+      return assertEqual (.ofList [
+        ('a', 1)
+      ]) $ Etl.transform (.ofList [
+        (1, ['A'])
+      ]))
   |>.addTest "single score with multiple letters" (do
-      return assertEqual (.ofList [('a', 1), ('e', 1), ('i', 1), ('o', 1), ('u', 1)])
-          (Etl.transform (.ofList [(1, ['A','E','I','O','U'])])))
+      return assertEqual (.ofList [
+        ('a', 1),
+        ('e', 1),
+        ('i', 1),
+        ('o', 1),
+        ('u', 1)
+      ]) $ Etl.transform (.ofList [
+        (1, ['A', 'E', 'I', 'O', 'U'])
+      ]))
   |>.addTest "multiple scores with multiple letters" (do
-      return assertEqual (.ofList [('a', 1), ('d', 2), ('e', 1), ('g', 2)])
-          (Etl.transform (.ofList [(1, ['A','E']), (2, ['D','G'])])))
+      return assertEqual (.ofList [
+        ('a', 1),
+        ('d', 2),
+        ('e', 1),
+        ('g', 2)
+      ]) $ Etl.transform (.ofList [
+        (1, ['A', 'E']),
+        (2, ['D', 'G'])
+      ]))
   |>.addTest "multiple scores with differing numbers of letters" (do
-      return assertEqual (.ofList [('a', 1), ('b', 3), ('c', 3), ('d', 2), ('e', 1), ('f', 4), ('g', 2), ('h', 4), ('i', 1), ('j', 8), ('k', 5), ('l', 1), ('m', 3), ('n', 1), ('o', 1), ('p', 3), ('q', 10), ('r', 1), ('s', 1), ('t', 1), ('u', 1), ('v', 4), ('w', 4), ('x', 8), ('y', 4), ('z', 10)])
-          (Etl.transform (.ofList [(1, ['A','E','I','O','U','L','N','R','S','T']), (10, ['Q','Z']), (2, ['D','G']), (3, ['B','C','M','P']), (4, ['F','H','V','W','Y']), (5, ['K']), (8, ['J','X'])])))
+      return assertEqual (.ofList [
+        ('a', 1),
+        ('b', 3),
+        ('c', 3),
+        ('d', 2),
+        ('e', 1),
+        ('f', 4),
+        ('g', 2),
+        ('h', 4),
+        ('i', 1),
+        ('j', 8),
+        ('k', 5),
+        ('l', 1),
+        ('m', 3),
+        ('n', 1),
+        ('o', 1),
+        ('p', 3),
+        ('q', 10),
+        ('r', 1),
+        ('s', 1),
+        ('t', 1),
+        ('u', 1),
+        ('v', 4),
+        ('w', 4),
+        ('x', 8),
+        ('y', 4),
+        ('z', 10)
+      ]) $ Etl.transform (.ofList [
+        (1, ['A', 'E', 'I', 'O', 'U', 'L', 'N', 'R', 'S', 'T']),
+        (10, ['Q', 'Z']),
+        (2, ['D', 'G']),
+        (3, ['B', 'C', 'M', 'P']),
+        (4, ['F', 'H', 'V', 'W', 'Y']),
+        (5, ['K']),
+        (8, ['J', 'X'])
+      ]))
 
 def main : IO UInt32 := do
   runTestSuitesWithExitCode [etlTests]
diff --git a/generators/Generator/Generator/EtlGenerator.lean b/generators/Generator/Generator/EtlGenerator.lean
index dcd21cc..d0ab15c 100644
--- a/generators/Generator/Generator/EtlGenerator.lean
+++ b/generators/Generator/Generator/EtlGenerator.lean
@@ -13,32 +13,39 @@ import {exercise}
 import Std
 
 open LeanTest
-open Std
 
-instance : BEq (HashMap Char Nat) where
-  beq h1 h2 :=
-    h1.size == h2.size &&
-    h1.fold (fun acc k v =>
-      acc && match h2.get? k with
-      | some v' => v == v'
-      | none    => false
-    ) true
+def Std.HashMap.toSortedList (map : Std.HashMap Char Nat) :=
+  map.toArray.qsort (λ (k1, _) (k2, _) => k1 ≤ k2)
+
+instance : BEq (Std.HashMap Char Nat) where
+  beq a b := a.toSortedList == b.toSortedList
 
 def {exercise.decapitalize}Tests : TestSuite :=
   (TestSuite.empty \"{exercise}\")"
 
+def mapJsonArray (array : Json) : String :=
+  array.getArr?
+    |> getOk
+    |>.map (λ v => s!"'{toLiteral v.compress}'")
+    |>.toList
+    |> (s!"{·}")
+
+def serializeLegacy (key : String) (val : Json) : String :=
+  s!"({key}, {mapJsonArray val})"
+
+def serializeOutput (key : String) (val : Json) : String :=
+  s!"('{key}', {val})"
+
 def genTestCase (exercise : String) (case : TreeMap.Raw String Json) : String :=
-  let input := case.get! "input" |> (·.getObjValD "legacy")
-  let legacyKeys := (getKeyValues input).map (λ (k, v) => (toLiteral k, v.replace "\"" "'"))
+  let input := case.get! "input" |>.getObjValD "legacy"
   let expected := case.get! "expected"
-  let expectedKeys := (getKeyValues expected).map (λ (k, v) => (s!"'{k}'", toLiteral v))
   let description := case.get! "description"
               |> (·.compress)
   let funName := getFunName (case.get! "property")
-  let call := s!"({exercise}.{funName} (.ofList {legacyKeys}))"
+  let call := s!"$ {exercise}.{funName} (.ofList {serializeObjectAsList input serializeLegacy})"
   s!"
   |>.addTest {description} (do
-      return assertEqual (.ofList {expectedKeys})\n          {call})"
+      return assertEqual (.ofList {serializeObjectAsList expected serializeOutput}) {call})"
 
 def genEnd (exercise : String) : String :=
   s!"