all the refactor

cmd/cart/projection_cache_test.go

@@ -0,0 +1,170 @@
+package main
+
+import (
+	"testing"
+
+	"git.k6n.net/mats/platform/catalog"
+	"git.k6n.net/mats/platform/money"
+)
+
+// TestProjectionCache_ApplyUpserts covers the happy path: a batch of N
+// projections reaches the cache via Apply, all are visible via Get.
+func TestProjectionCache_ApplyUpserts(t *testing.T) {
+	c := newCatalogProjectionCache()
+	updates := []catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{ID: "id-A", SKU: "A", PriceIncVat: money.Cents(100_00), TaxClass: "standard"}},
+		{Projection: catalog.Projection{ID: "id-B", SKU: "B", PriceIncVat: money.Cents(150_00), TaxClass: "reduced"}},
+		{Projection: catalog.Projection{ID: "id-C", SKU: "C", PriceIncVat: money.Cents(0), TaxClass: ""}},
+	}
+	upserts, deletes := c.Apply(updates)
+	if upserts != 3 || deletes != 0 {
+		t.Fatalf("counts: upserts=%d deletes=%d, want 3/0", upserts, deletes)
+	}
+	for _, want := range []struct {
+		sku    string
+		price  money.Cents
+		taxCls string
+	}{
+		{"A", money.Cents(100_00), "standard"},
+		{"B", money.Cents(150_00), "reduced"},
+		{"C", money.Cents(0), ""},
+	} {
+		got, ok := c.Get(want.sku)
+		if !ok {
+			t.Fatalf("Get(%q): missing", want.sku)
+		}
+		if got.PriceIncVat != want.price || got.TaxClass != want.taxCls {
+			t.Fatalf("Get(%q) = %+v, want price=%d taxCls=%q", want.sku, got, want.price, want.taxCls)
+		}
+	}
+	if c.Len() != 3 {
+		t.Fatalf("Len = %d, want 3", c.Len())
+	}
+}
+
+// TestProjectionCache_DeleteTombstone verifies that a delete update sets a
+// tombstone (not removes the entry), so:
+//   - Get returns (_, false) on a deleted SKU
+//   - IsDeleted returns true
+//   - the same entry continues to count toward Len (size accounting)
+func TestProjectionCache_DeleteTombstone(t *testing.T) {
+	c := newCatalogProjectionCache()
+	c.Apply([]catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{ID: "id-A", SKU: "A", PriceIncVat: money.Cents(100_00)}},
+	})
+	if _, ok := c.Get("A"); !ok {
+		t.Fatalf("A: expected hit before delete")
+	}
+
+	upserts, deletes := c.Apply([]catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{SKU: "A"}, Deleted: true},
+	})
+	if upserts != 0 || deletes != 1 {
+		t.Fatalf("delete counts: upserts=%d deletes=%d, want 0/1", upserts, deletes)
+	}
+
+	if got, ok := c.Get("A"); ok {
+		t.Fatalf("A after delete: got %+v ok=true, want miss", got)
+	}
+	if !c.IsDeleted("A") {
+		t.Fatalf("A after delete: IsDeleted false")
+	}
+	if c.IsDeleted("UNKNOWN") {
+		t.Fatalf("UNKNOWN: IsDeleted should be false (entry doesn't exist)")
+	}
+	if c.Len() != 1 {
+		t.Fatalf("Len after tombstone: %d, want 1 (tombstone still in map)", c.Len())
+	}
+}
+
+// TestProjectionCache_BusResurrect verifies that a fresh upsert after a delete
+// clears the tombstone (live entry replaces it): Get returns the projection,
+// IsDeleted flips to false. Mirrors how the live catalog keeps flipping state.
+func TestProjectionCache_BusResurrect(t *testing.T) {
+	c := newCatalogProjectionCache()
+	c.Apply([]catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{SKU: "A", PriceIncVat: money.Cents(50_00)}},
+		{Projection: catalog.Projection{SKU: "A"}, Deleted: true},
+	})
+	if !c.IsDeleted("A") {
+		t.Fatalf("A: not tombstoned after delete")
+	}
+
+	c.Apply([]catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{SKU: "A", PriceIncVat: money.Cents(75_00)}},
+	})
+
+	got, ok := c.Get("A")
+	if !ok {
+		t.Fatalf("A: expected live after re-upsert")
+	}
+	if got.PriceIncVat != money.Cents(75_00) {
+		t.Fatalf("A re-upsert price = %d, want 7500", got.PriceIncVat)
+	}
+	if c.IsDeleted("A") {
+		t.Fatalf("A: still tombstoned after re-upsert")
+	}
+}
+
+// TestProjectionCache_EmptySKUIgnored validates that an upsert with an empty
+// SKU is a no-op (defensive — bus should never publish "" but cheaper to log
+// + drop than to populate an ambiguous cache slot).
+func TestProjectionCache_EmptySKUIgnored(t *testing.T) {
+	c := newCatalogProjectionCache()
+	upserts, _ := c.Apply([]catalog.ProjectionUpdate{
+		{Projection: catalog.Projection{SKU: "", PriceIncVat: money.Cents(100_00)}},
+	})
+	if upserts != 0 {
+		t.Fatalf("empty-SKU upsert: %d, want 0", upserts)
+	}
+	if c.Len() != 0 {
+		t.Fatalf("Len after empty-SKU: %d, want 0", c.Len())
+	}
+}
+
+// TestProjectionCache_BusRaceSafe runs Apply + Get concurrently under -race
+// to lock down the lock order. Run via `go test -race ./cmd/cart/...`.
+func TestProjectionCache_BusRaceSafe(t *testing.T) {
+	c := newCatalogProjectionCache()
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		for i := 0; i < 500; i++ {
+			c.Apply([]catalog.ProjectionUpdate{
+				{Projection: catalog.Projection{SKU: "X", PriceIncVat: money.Cents(int64(i * 100))}},
+			})
+		}
+	}()
+	for i := 0; i < 2000; i++ {
+		_, _ = c.Get("X")
+		_ = c.IsDeleted("X")
+		_ = c.Len()
+	}
+	<-done
+	if _, ok := c.Get("X"); !ok {
+		t.Fatalf("final Get(X): miss after concurrent writes")
+	}
+}
+
+// TestTaxResolveBp covers the static TaxClass→bp mapping used by
+// ApplyProjectionOverlay. Adds a regression net for the common Nordic rates.
+func TestTaxResolveBp(t *testing.T) {
+	cases := []struct {
+		class string
+		want  int
+	}{
+		{"standard", 2500},
+		{"reduced", 1200},
+		{"lowered", 600},
+		{"zero", 0},
+		{"exempt", 0},
+		{"", 2500}, // missing class defaults to standard (matches mutation registry)
+		{"unknown-class", 2500},
+	}
+	for _, tc := range cases {
+		got := resolveTaxBp(tc.class)
+		if got != tc.want {
+			t.Errorf("resolveTaxBp(%q) = %d, want %d", tc.class, got, tc.want)
+		}
+	}
+}