@Test
public void applySystemPropertiesShouldConvertOptsToSystemProps() {

  System.setProperty("c", "");
  Map<String, String> opts = new HashMap<>();
  opts.put("a", "1");
  opts.put("-Dc", "2");
  CoffeeHouseApp.applySystemProperties(opts);
  assertThat(System.getProperty("c")).isEqualTo("2");
}