fix: deliver validated AI insight responses

internal/growthreport/adapter_test.go

@@ -0,0 +1,49 @@
+package growthreport
+
+import (
+	"testing"
+	"time"
+
+	"git.amiirkhl.ir/starcoach-hackathon/zarinpal-analytics-backend/internal/growth"
+)
+
+func TestUpcomingEventsKeepsFiveChronologicalEligibleCandidates(t *testing.T) {
+	t.Parallel()
+	start := time.Date(2026, time.August, 22, 0, 0, 0, 0, time.UTC)
+	catalog := []growth.Event{
+		{ID: "past", TitleFA: "رویداد گذشته", StartDate: start.AddDate(0, 0, -1)},
+		{ID: "one", TitleFA: "رویداد اول", StartDate: start},
+		{ID: "two", TitleFA: "رویداد دوم", StartDate: start.AddDate(0, 0, 40)},
+		{ID: "three", TitleFA: "رویداد سوم", StartDate: start.AddDate(0, 0, 100)},
+		{ID: "four", TitleFA: "رویداد چهارم", StartDate: start.AddDate(0, 0, 190)},
+		{ID: "five", TitleFA: "رویداد پنجم", StartDate: start.AddDate(0, 0, 280), OfficialHoliday: true},
+		{ID: "six", TitleFA: "رویداد ششم", StartDate: start.AddDate(0, 0, 320)},
+	}
+
+	got := upcomingEvents(catalog, start, 5)
+	if len(got) != 5 {
+		t.Fatalf("upcomingEvents() returned %d events, want 5", len(got))
+	}
+	for index, want := range []string{"event:one", "event:two", "event:three", "event:four", "event:five"} {
+		if got[index].EvidenceID != want {
+			t.Fatalf("upcomingEvents()[%d] = %q, want %q", index, got[index].EvidenceID, want)
+		}
+	}
+	if !got[4].OfficialHoliday {
+		t.Fatal("eligible official holiday was removed from the candidate set")
+	}
+}
+
+func TestFallbackEventRecommendationsUseTheFirstThreeCandidates(t *testing.T) {
+	t.Parallel()
+	events := []UpcomingEvent{{EvidenceID: "event:first"}, {EvidenceID: "event:second"}, {EvidenceID: "event:third"}, {EvidenceID: "event:fourth"}}
+	got := fallbackEventRecommendations(events)
+	if len(got) != 3 || got[0].EvidenceID != "event:first" || got[2].EvidenceID != "event:third" {
+		t.Fatalf("fallbackEventRecommendations() = %+v", got)
+	}
+	for _, item := range got {
+		if item.RelevanceReason == "" {
+			t.Fatal("fallback recommendation lacks a relevance reason")
+		}
+	}
+}