@Test
  public void testMessageWithCreate() {
    String displayId = DisplayUtil.getId(shell.getDisplay());
    String[] styles = new String[] {"TRIM", "FOO"};

    writer.appendCreate(shellId, "org.Text");
    writer.appendSet(shellId, "parent", displayId);
    writer.appendSet(shellId, "style", JsonUtil.createJsonArray(styles));
    writer.appendSet(shellId, "key1", "a");
    writer.appendSet(shellId, "key2", "b");

    CreateOperation operation = (CreateOperation) getMessage().getOperation(0);
    assertEquals(shellId, operation.getTarget());
    assertEquals(displayId, operation.getParent());
    assertEquals("org.Text", operation.getType());
    assertArrayEquals(styles, operation.getStyles());
    assertEquals("a", operation.getProperty("key1").asString());
    assertEquals("b", operation.getProperty("key2").asString());
  }