fix(growth): validate reviewed event catalog

internal/growth/catalog_test.go

@@ -0,0 +1,60 @@
+package growth
+
+import "testing"
+
+func TestCatalog1405IsValidAndDefensivelyCopied(t *testing.T) {
+	first := Catalog1405()
+	if err := ValidateCatalog(first); err != nil {
+		t.Fatalf("catalog should be valid: %v", err)
+	}
+	first[0].Tags[0] = "mutated"
+	second := Catalog1405()
+	if second[0].Tags[0] == "mutated" {
+		t.Fatal("catalog tags escaped through a shared backing array")
+	}
+}
+
+func TestValidateCatalogRejectsDuplicateAndIncompleteEvents(t *testing.T) {
+	event := catalogEvent("duplicate", "رویداد", "2026-01-01", "2026-01-01", "family", EventOfficial, []string{"tag"})
+	if err := ValidateCatalog([]Event{event, event}); err == nil {
+		t.Fatal("expected duplicate id error")
+	}
+	event.Source = ""
+	if err := ValidateCatalog([]Event{event}); err == nil {
+		t.Fatal("expected missing source error")
+	}
+}
+
+func TestAnalyzeEventEffectExcludesCatalogEventsFromBaseline(t *testing.T) {
+	target := Event{ID: "target", StartDate: date("2026-05-02"), EndDate: date("2026-05-02")}
+	excluded := Event{ID: "other", StartDate: target.StartDate.AddDate(0, 0, -7), EndDate: target.StartDate.AddDate(0, 0, -7)}
+	history := make([]DailyPoint, 0, 9)
+	for week := 1; week <= 8; week++ {
+		count := int64(30)
+		if week == 1 {
+			count = 1_000
+		}
+		history = append(history, DailyPoint{Date: target.StartDate.AddDate(0, 0, -7*week), SessionCount: count, PaidSessionCount: count, PaidAmountRial: count * 100})
+	}
+	history = append(history, DailyPoint{Date: target.StartDate, SessionCount: 50, PaidSessionCount: 50, PaidAmountRial: 5_000})
+	effect := AnalyzeEventEffect(history, target, []Event{excluded})
+	if effect.ObservationCount != 7 || effect.BaselineSessionCount != 30 || !effect.MaterialWin {
+		t.Fatalf("catalog event polluted baseline: %+v", effect)
+	}
+}
+
+func TestForecastSuppressesPoorBacktest(t *testing.T) {
+	start := date("2026-07-01")
+	history := make([]DailyPoint, 0, 90)
+	for i := 90; i > 0; i-- {
+		value := int64(100)
+		if i%2 == 0 {
+			value = 1_000
+		}
+		history = append(history, DailyPoint{Date: start.AddDate(0, 0, -i), SessionCount: value, PaidSessionCount: value, PaidAmountRial: value * 1_000})
+	}
+	forecast := BuildForecast(history, nil, start, 90)
+	if forecast.Confidence != ConfidenceInsufficientData || len(forecast.Points) != 0 {
+		t.Fatalf("poor model should be suppressed: %+v", forecast)
+	}
+}