Files
scrabble-game/backend/internal/engine/bag_test.go
T
Ilia Denisov 6d0dd4fb14
Tests · Go / test (push) Successful in 6s
Tests · Integration / integration (push) Successful in 7s
Stage 2: engine package over scrabble-solver (registry, bag, Game, replay)
backend/internal/engine wraps the sibling scrabble-solver library in-process:

- Registry: versioned DAWG load via dafsa.Load, keyed by (variant, dict_version),
  latest-per-variant; English / Russian / Эрудит handled uniformly.
- Bag: own deterministic, seeded tile bag with Draw + Return (for exchanges),
  since the solver's self-play bag cannot return tiles.
- Game: pure rules engine — deal, play/pass/exchange/resign, refill, per-move
  scoring, turn order, and end-condition detection (empty bag + empty rack, six
  scoreless turns, resignation) with end-game rack adjustment.
- decode/ReplayBoard: dictionary-independent MoveRecords and board replay via
  scrabble.Apply (no internal/encoding), realising ARCHITECTURE §9.1.

Wiring: go.work gains "replace scrabble-solver => ../scrabble-solver"; backend
requires scrabble-solver (placeholder) and github.com/iliadenisov/dafsa directly.
Both Go CI workflows clone the public solver sibling (master HEAD, no token) and
set BACKEND_DICT_DIR.

Docs: ARCHITECTURE §5/§14, TESTING engine layer, backend README, and PLAN
refinements + deferred TODOs (publish/version solver; split engine vs dictionary
generator).
2026-06-02 15:10:08 +02:00

79 lines
2.0 KiB
Go

package engine
import (
"maps"
"slices"
"testing"
"scrabble-solver/rules"
)
// allTiles returns the full multiset of tiles a bag is filled from, in ruleset
// order (letters then blanks).
func allTiles(rs *rules.Ruleset) []byte {
var ts []byte
for i, n := range rs.Counts {
for range n {
ts = append(ts, byte(i))
}
}
for range rs.Blanks {
ts = append(ts, blankTile)
}
return ts
}
// TestBagDeterministic checks that two bags with the same seed draw identically.
func TestBagDeterministic(t *testing.T) {
rs := rules.English()
a, b := NewBag(rs, 42), NewBag(rs, 42)
if a.Len() != b.Len() {
t.Fatalf("len mismatch: %d vs %d", a.Len(), b.Len())
}
for a.Len() > 0 {
if da, db := a.Draw(3), b.Draw(3); !slices.Equal(da, db) {
t.Fatalf("same seed drew differently: %v vs %v", da, db)
}
}
}
// TestBagReturnConservesMultiset checks Len accounting and that Return puts the
// exact tiles back, leaving the bag's multiset unchanged.
func TestBagReturnConservesMultiset(t *testing.T) {
rs := rules.English()
want := tileCounts(allTiles(rs))
total := len(allTiles(rs))
b := NewBag(rs, 7)
if b.Len() != total {
t.Fatalf("new bag len = %d, want %d", b.Len(), total)
}
drawn := b.Draw(rs.RackSize)
if b.Len() != total-rs.RackSize {
t.Fatalf("after draw len = %d, want %d", b.Len(), total-rs.RackSize)
}
b.Return(drawn)
if b.Len() != total {
t.Fatalf("after return len = %d, want %d", b.Len(), total)
}
if got := tileCounts(b.Draw(b.Len())); !maps.Equal(got, want) {
t.Fatalf("multiset changed across draw/return")
}
}
// TestBagDrawAll returns everything once the bag is exhausted and never panics.
func TestBagDrawAll(t *testing.T) {
rs := rules.English()
b := NewBag(rs, 1)
all := b.Draw(b.Len() + 10) // asking for more than present returns all
if len(all) != len(allTiles(rs)) {
t.Fatalf("drew %d, want %d", len(all), len(allTiles(rs)))
}
if b.Len() != 0 {
t.Fatalf("bag len = %d, want 0", b.Len())
}
if got := b.Draw(1); len(got) != 0 {
t.Fatalf("draw from empty bag returned %d tiles", len(got))
}
}