test(load): add idle and tunable group scenarios

loadtest/im-pressure/agent_history_test.go

@@ -76,6 +76,33 @@ func TestScenarioUsersScaleWithConfiguredCapacity(t *testing.T) {
 	}
 }
 
+func TestReconnectBackoffCapsAndJitters(t *testing.T) {
+	minWait := 2 * time.Second
+	maxWait := 30 * time.Second
+	first := reconnectBackoff(minWait, maxWait, 1, 10)
+	if first < minWait || first >= minWait+minWait/4 {
+		t.Fatalf("first backoff=%s outside expected jitter range", first)
+	}
+	capped := reconnectBackoff(minWait, maxWait, 10, 10)
+	if capped < maxWait || capped >= maxWait+maxWait/4 {
+		t.Fatalf("capped backoff=%s outside expected jitter range", capped)
+	}
+	if reconnectBackoff(minWait, maxWait, 3, 10) == reconnectBackoff(minWait, maxWait, 3, 11) {
+		t.Fatal("different account indexes should receive different jitter")
+	}
+}
+
+func TestValidScenarioIncludesIdle(t *testing.T) {
+	for _, scenario := range []string{"p2p", "group", "mixed", "idle"} {
+		if !validScenario(scenario) {
+			t.Fatalf("scenario %s should be valid", scenario)
+		}
+	}
+	if validScenario("unknown") {
+		t.Fatal("unknown scenario should be rejected")
+	}
+}
+
 func TestNewHistoryQueryIncludesInterleavedSequenceRange(t *testing.T) {
 	messages := make([]AcceptedMessage, 10)
 	for i := range messages {