.that(shutdownAndAwaitTermination(closingExecutor, 10, SECONDS))
        .isTrue();
    if (!failures.isEmpty()) {
      StringWriter message = new StringWriter();
      PrintWriter writer = new PrintWriter(message);
      writer.println("Expected no failures, but found:");
      for (AssertionError failure : failures) {
        failure.printStackTrace(writer);
      }
      failures.clear();

    ArbitraryInstances.get(PrintStream.class).println("test");
    ArbitraryInstances.get(PrintWriter.class).println("test");
    assertNotNull(ArbitraryInstances.get(File.class));
    assertFreshInstanceReturned(
        ByteArrayOutputStream.class, OutputStream.class,
        Writer.class, StringWriter.class,
        PrintStream.class, PrintWriter.class);
    assertEquals(ByteSource.empty(), ArbitraryInstances.get(ByteSource.class));