refactor lot matching into shared module

internal/warehouse/snapshot_test.go

@@ -0,0 +1,103 @@
+package warehouse
+
+import (
+	"math"
+	"slices"
+	"testing"
+	"time"
+
+	"git.mchus.pro/mchus/quoteforge/internal/models"
+	"github.com/glebarez/sqlite"
+	"gorm.io/gorm"
+)
+
+func TestComputePricelistItemsFromStockLog(t *testing.T) {
+	db := openTestDB(t)
+	if err := db.AutoMigrate(&models.Lot{}, &models.LotPartnumber{}, &models.StockLog{}); err != nil {
+		t.Fatalf("automigrate: %v", err)
+	}
+
+	if err := db.Create(&models.Lot{LotName: "CPU_X"}).Error; err != nil {
+		t.Fatalf("seed lot: %v", err)
+	}
+	if err := db.Create(&models.LotPartnumber{Partnumber: "PN-CPU-X", LotName: "CPU_X"}).Error; err != nil {
+		t.Fatalf("seed mapping: %v", err)
+	}
+
+	qtySmall := 1.0
+	qtyBig := 9.0
+	now := time.Now()
+	rows := []models.StockLog{
+		{Partnumber: "PN CPU X", Date: now, Price: 100, Qty: &qtySmall},
+		{Partnumber: "CPU_X-EXTRA", Date: now, Price: 200, Qty: &qtyBig},
+	}
+	if err := db.Create(&rows).Error; err != nil {
+		t.Fatalf("seed stock rows: %v", err)
+	}
+
+	items, err := ComputePricelistItemsFromStockLog(db)
+	if err != nil {
+		t.Fatalf("ComputePricelistItemsFromStockLog: %v", err)
+	}
+	if len(items) != 1 {
+		t.Fatalf("expected 1 item, got %d", len(items))
+	}
+	if items[0].LotName != "CPU_X" {
+		t.Fatalf("expected lot CPU_X, got %s", items[0].LotName)
+	}
+	if math.Abs(items[0].Price-200) > 0.001 {
+		t.Fatalf("expected weighted median 200, got %f", items[0].Price)
+	}
+}
+
+func TestLoadLotMetricsLatestOnlyIncludesPartnumbers(t *testing.T) {
+	db := openTestDB(t)
+	if err := db.AutoMigrate(&models.Lot{}, &models.LotPartnumber{}, &models.StockLog{}); err != nil {
+		t.Fatalf("automigrate: %v", err)
+	}
+
+	if err := db.Create(&models.Lot{LotName: "CPU_X"}).Error; err != nil {
+		t.Fatalf("seed lot: %v", err)
+	}
+	if err := db.Create(&models.LotPartnumber{Partnumber: "PN-MAPPED", LotName: "CPU_X"}).Error; err != nil {
+		t.Fatalf("seed mapping: %v", err)
+	}
+
+	oldDate := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
+	newDate := time.Date(2026, 1, 2, 0, 0, 0, 0, time.UTC)
+	oldQty := 10.0
+	newQty := 3.0
+	rows := []models.StockLog{
+		{Partnumber: "CPU_X-001", Date: oldDate, Price: 100, Qty: &oldQty},
+		{Partnumber: "CPU_X-001", Date: newDate, Price: 100, Qty: &newQty},
+	}
+	if err := db.Create(&rows).Error; err != nil {
+		t.Fatalf("seed stock rows: %v", err)
+	}
+
+	qtyByLot, pnsByLot, err := LoadLotMetrics(db, []string{"CPU_X"}, true)
+	if err != nil {
+		t.Fatalf("LoadLotMetrics: %v", err)
+	}
+
+	if got := qtyByLot["CPU_X"]; math.Abs(got-3.0) > 0.001 {
+		t.Fatalf("expected latest qty 3, got %f", got)
+	}
+
+	pns := pnsByLot["CPU_X"]
+	if !slices.Contains(pns, "PN-MAPPED") {
+		t.Fatalf("expected mapped PN-MAPPED in partnumbers, got %v", pns)
+	}
+	if !slices.Contains(pns, "CPU_X-001") {
+		t.Fatalf("expected stock CPU_X-001 in partnumbers, got %v", pns)
+	}
+}
+
+func openTestDB(t *testing.T) *gorm.DB {
+	t.Helper()
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("open sqlite: %v", err)
+	}
+	return db
+}