@Test
public void should_migrate_page_with_data_with_null_value() throws Exception {

    Page pageWithData = aPage().withId("pageWithData").withData("myEmptyData", 
            DataBuilder.aConstantData().exposed(true).build()).build();
    dataToVariableMigrationStep.migrate(pageWithData);
    Variable variable = pageWithData.getVariables().get("myEmptyData");
    assertThat(variable.getValue()).isEmpty();
    assertThat(variable.isExposed()).isTrue();
    assertThat(pageWithData.getData()).isNull();
}