diff --git a/spec/lib/port_pool_spec.rb b/spec/lib/port_pool_spec.rb
index 95f75686..c638cb09 100644
--- a/spec/lib/port_pool_spec.rb
+++ b/spec/lib/port_pool_spec.rb
@@ -22,7 +22,7 @@ describe PortPool do
       it 'returns the port' do
         available_ports = described_class.instance_variable_get(:@available_ports)
         described_class.instance_variable_set(:@available_ports, [])
-        expect(described_class.available_port).to be_nil
+        expect(described_class.available_port).to be nil
         described_class.instance_variable_set(:@available_ports, available_ports)
       end
     end