@Test
  public void testMerge_whenInstantiatedWithEmptyAndNotMergedWithNull_shouldReturnOther() {
    // run
    final Configuration mergedConfig =
        mergeStrategy.merge(ConfigBuilder.getEmptyConfiguration(), otherConfig);

    // assert
    assertSame(mergedConfig, otherConfig);
  }
 @Test
 public void testMerge_whenMergedWithEmpty_shouldReturnBaseConfig() {
   final Configuration mergedConfig =
       mergeStrategy.merge(baseConfig, ConfigBuilder.getEmptyConfiguration());
   assertSame(baseConfig, mergedConfig);
 }