@Test
  public void hasJavaSourceFiles() {
    final DefaultProjectFileSystem fs = newDefaultProjectFileSystem(project);
    assertThat(fs.hasJavaSourceFiles(), is(true));

    PropertiesConfiguration conf = new PropertiesConfiguration();
    conf.setProperty(CoreProperties.PROJECT_EXCLUSIONS_PROPERTY, "**/*.java");
    project.setConfiguration(conf);
    assertThat(fs.hasJavaSourceFiles(), is(false));
  }