feat: add retention policy and stability verification

internal/retention/policy_test.go

@@ -0,0 +1,65 @@
+package retention
+
+import (
+	"testing"
+
+	core "git.yuntuo.hk/k2safe/orbit/model"
+)
+
+func TestDefaultsAndValidation(t *testing.T) {
+	ns, err := core.NewID()
+	if err != nil {
+		t.Fatal(err)
+	}
+	p := Defaults(ns)
+	if p.Enabled || p.Source != "default" || p.IdempotencyDays != 90 || p.TaskHistoryDays != 365 || p.AuditLogDays != 2555 {
+		t.Fatalf("unexpected defaults: %+v", p)
+	}
+	if err := p.Validate(); err != nil {
+		t.Fatal(err)
+	}
+	p.IdempotencyDays = 89
+	if err := p.Validate(); err == nil {
+		t.Fatal("accepted an idempotency window shorter than the safety minimum")
+	}
+}
+
+func TestUpdateInputRequiresReasonAndKeepsSafetyMinimum(t *testing.T) {
+	ns, _ := core.NewID()
+	in := UpdateInput{
+		IdempotencyDays: 90, TaskHistoryDays: 30, WorkflowHistoryDays: 30,
+		EventLogDays: 30, DeliveryHistoryDays: 30, InboxHistoryDays: 30,
+		AuditLogDays: 365, Reason: "quarterly retention review",
+	}
+	if _, err := in.ToPolicy(ns); err != nil {
+		t.Fatal(err)
+	}
+	in.Reason = ""
+	if _, err := in.ToPolicy(ns); err == nil {
+		t.Fatal("accepted an empty audit reason")
+	}
+	in.Reason = "shorten"
+	in.IdempotencyDays = 89
+	if _, err := in.ToPolicy(ns); err == nil {
+		t.Fatal("accepted an unsafe idempotency window")
+	}
+}
+
+func TestFromEnvOverridesOnlyDeploymentDefaults(t *testing.T) {
+	values := map[string]string{
+		"ORBIT_RETENTION_IDEMPOTENCY_DAYS": "120",
+		"ORBIT_RETENTION_TASK_DAYS":        "180",
+		"ORBIT_RETENTION_AUDIT_DAYS":       "730",
+	}
+	p, err := FromEnv(func(k string) string { return values[k] })
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.IdempotencyDays != 120 || p.TaskHistoryDays != 180 || p.AuditLogDays != 730 || p.EventLogDays != DefaultEventLogDays {
+		t.Fatalf("environment defaults not applied: %+v", p)
+	}
+	values["ORBIT_RETENTION_IDEMPOTENCY_DAYS"] = "89"
+	if _, err := FromEnv(func(k string) string { return values[k] }); err == nil {
+		t.Fatal("accepted unsafe environment idempotency window")
+	}
+}