webSocket: WebSocket,
          code: Int,
          reason: String,
        ) {
          webSocket.close(1000, null)
        }
      },
    )
    server.close(1001, "bye")
    clientListener.assertClosed(1001, "bye")
    clientListener.assertExhausted()
    serverListener.assertClosing(1000, "")
    serverListener.assertClosed(1000, "")
    serverListener.assertExhausted()
  }

  @Test

    assertThrows(NullPointerException.class, () -> result.hasNext());
    assertThrows(NullPointerException.class, () -> result.next());
    // There is no way to get "through" to the 3.  Buh-bye
  }

  public void testConcatVarArgsContainingNull() {
    assertThrows(
        NullPointerException.class,
        () ->
            Iterators.concat(

<p>
Strings can be concatenated using the <code>+</code> operator
or the <code>+=</code> assignment operator:
</p>

<pre>
s := "hi" + string(c)
s += " and good bye"
</pre>

<p>
String addition creates a new string by concatenating the operands.
</p>

<h3 id="Comparison_operators">Comparison operators</h3>

<p>