diff --git a/internal/ircserver/server_test.go b/internal/ircserver/server_test.go
index 3b7eabf..a530b36 100644
--- a/internal/ircserver/server_test.go
+++ b/internal/ircserver/server_test.go
@@ -645,8 +645,6 @@ func TestNewPingTimes(t *testing.T) {
 func TestIdleCleanupKeepsActiveUser(t *testing.T) {
 	t.Parallel()
 
-	const idleTimeout = 500 * time.Millisecond
-
 	env := newTestEnv(t)
 
 	active := env.dial(t)
@@ -655,13 +653,17 @@ func TestIdleCleanupKeepsActiveUser(t *testing.T) {
 	idle := env.dial(t)
 	idle.register("idle")
 
-	time.Sleep(idleTimeout)
+	// Both users were last seen before cutoff, and only active
+	// sends a command after it, so the result does not depend
+	// on how long the PONG takes to arrive.
+	cutoff := time.Now()
+
 	active.sendAndExpect("PING :still here", "PONG")
 
 	// The idle cleanup in internal/handlers removes exactly
 	// the users this returns.
 	stale, err := env.database.GetStaleOrphanSessions(
-		t.Context(), time.Now().Add(-idleTimeout),
+		t.Context(), cutoff,
 	)
 	if err != nil {
 		t.Fatalf("get stale sessions: %v", err)