From 46d94d86705a7fd0a7c5d0d7c6a74f11669641ca Mon Sep 17 00:00:00 2001
From: Arnaud Bailly <arnaud@pankzsoft.com>
Date: Mon, 27 Oct 2025 16:26:55 +0100
Subject: Add more tests and references

---
 .../haskell/test/Minilang/Lambda/EvalSpec.hs       | 24 ++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

(limited to 'lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs')

diff --git a/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs b/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
index df933a4..11cf394 100644
--- a/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
+++ b/lambda-calcul/haskell/test/Minilang/Lambda/EvalSpec.hs
@@ -7,9 +7,16 @@ import Test.Hspec (Spec, describe, it, shouldBe)
 
 spec :: Spec
 spec = do
-  let fix = Lam "x" (App (Var "x") (Var "x"))
+  let fix =
+        Lam
+          "f"
+          ( App
+              (Lam "x" (App (Var "f") (App (Var "x") (Var "x"))))
+              (Lam "x" (App (Var "f") (App (Var "x") (Var "x"))))
+          )
   let omega = App fix fix
   let term = App (App (Lam "x" (Lam "y" (Var "y"))) omega) (Var "z")
+  let fst' = Lam "x" (Lam "y" (Var "x"))
 
   describe "call-by-value eval" $ do
     it "evaluates 'x' as itself" $ do
@@ -18,12 +25,16 @@ spec = do
     it "evaluates '((λ x. x) y)' as 'y'" $ do
       let term = App (Lam "x" (Var "x")) (Var "y")
       eval term [] `shouldBe` Var "y"
-    it "evaluates '((λ x y. y) y z t)' as '(z t)'" $ do
+    it "evaluates '((λ x y. y) z t y)' as '(t y)'" $ do
       let snd' = Lam "x" (Lam "y" (Var "y"))
-      let term = App (App (App snd' (Var "y")) (Var "z")) (Var "t")
-      eval term [] `shouldBe` App (Var "z") (Var "t")
+      let term = App (App (App snd' (Var "z")) (Var "t")) (Var "y")
+      eval term [] `shouldBe` App (Var "t") (Var "y")
+    it "evaluates '((λ x y. x) z t)' as 'z'" $ do
+      let term = App (App fst' (Var "z")) (Var "t")
+      eval term [] `shouldBe` Var "z"
     it "diverges on evaluating argument bound to ω" $
-      shouldDiverge $ eval term []
+      shouldDiverge $
+        eval term []
 
   describe "call-by-need eval" $ do
     it "evaluates 'x' as itself" $ do
@@ -31,7 +42,8 @@ spec = do
     it "evaluates '(λ x y . y) ⊥ z' as 'z'" $ do
       evalNeed term [] `shouldBe` Var "z"
     it "diverges on evaluating ω" $
-      shouldDiverge $ evalNeed omega []
+      shouldDiverge $
+        evalNeed omega []
 
 shouldDiverge :: Term -> IO ()
 shouldDiverge t =
-- 
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