### Question:
LocalConfigurationService implements LocalConfiguration, Serializable { private String read(final LocalConfiguration d, final String entryKey) { return ofNullable(d.get(entryKey)).orElseGet(() -> d.get(entryKey.replace('.', '_'))); }  @Override String get(final String key); @Override Set<String> keys();  }### Answer:
@Test void read() { System.setProperty("LocalConfigurationServiceTest.test.foo", "1"); try { assertEquals("1", new LocalConfigurationService(singletonList(systemProperties), "LocalConfigurationServiceTest") .get("test.foo")); } finally { System.clearProperty("LocalConfigurationServiceTest.test.foo"); } }