backend/internal/inttest/norepeat_test.go

@@ -4,6 +4,7 @@ package inttest
 
 import (
 	"context"
+	"errors"
 	"testing"
 
 	"github.com/google/uuid"
@@ -64,23 +65,38 @@ func TestNoRepeatWordsPinnedFromTheVariant(t *testing.T) {
 func TestNoRepeatWordsHonoursThePinNotTheVariant(t *testing.T) {
 	ctx := context.Background()
 	svc := newGameService()
-	g := createTwoSeatGame(t, svc, engine.VariantErudit)
 
-	if _, err := testDB.ExecContext(ctx,
+	// Each game draws from a bag seeded with crypto/rand, so an opening rack occasionally has no
-		`UPDATE backend.games SET no_repeat_words = false WHERE game_id = $1`, g.ID); err != nil {
+	// playable word at all. That is a legitimate engine answer which says nothing about the pin
-		t.Fatalf("clear the pin: %v", err)
+	// under test, and taking it for a failure made this test flake (~1 run in 300 on the committed
-	}
+	// dictionary, and more often on another one). Retry with fresh games instead: one unlucky draw
+	// no longer decides the result, while a genuinely broken path still fails every attempt.
+	const draws = 5
+	for attempt := 1; ; attempt++ {
+		g := createTwoSeatGame(t, svc, engine.VariantErudit)
+		if _, err := testDB.ExecContext(ctx,
+			`UPDATE backend.games SET no_repeat_words = false WHERE game_id = $1`, g.ID); err != nil {
+			t.Fatalf("clear the pin: %v", err)
+		}
 
-	reloaded, err := svc.GameByID(ctx, g.ID)
+		reloaded, err := svc.GameByID(ctx, g.ID)
-	if err != nil {
+		if err != nil {
-		t.Fatalf("get game: %v", err)
+			t.Fatalf("get game: %v", err)
-	}
+		}
-	if reloaded.NoRepeatWords {
+		if reloaded.NoRepeatWords {
-		t.Fatal("an Erudit game whose row has the rule off must report it off")
+			t.Fatal("an Erudit game whose row has the rule off must report it off")
-	}
+		}
-	// The rule reaches the engine from the row, so the reconstructed game plays unrestricted:
+		// The rule reaches the engine from the row, so the reconstructed game plays unrestricted:
-	// its generated moves are the solver's full list, none filtered away.
+		// its generated moves are the solver's full list, none filtered away.
-	if _, err := svc.Hint(ctx, reloaded.ID, reloaded.Seats[reloaded.ToMove].AccountID); err != nil {
+		_, err = svc.Hint(ctx, reloaded.ID, reloaded.Seats[reloaded.ToMove].AccountID)
-		t.Fatalf("hint on an unrestricted Erudit game: %v", err)
+		if err == nil {
+			return
+		}
+		if !errors.Is(err, game.ErrNoHintAvailable) {
+			t.Fatalf("hint on an unrestricted Erudit game: %v", err)
+		}
+		if attempt == draws {
+			t.Fatalf("no opening rack in %d games had a playable move", draws)
+		}
 	}
 }