### Question:
Configuration { public Builder toBuilder() { return new Builder(this); } private  Configuration(Builder builder); static Configuration unix(); static Configuration osX(); static Configuration windows(); static Configuration forCurrentPlatform(); static Builder builder(PathType pathType); @Override String toString(); Builder toBuilder();  }### Answer:
@Test public void testToBuilder() { Configuration config = Configuration.unix().toBuilder() .setWorkingDirectory("/hello/world") .setAttributeViews("basic", "posix") .build(); assertThat(config.pathType).isEqualTo(PathType.unix()); assertThat(config.roots).containsExactly("/"); assertThat(config.workingDirectory).isEqualTo("/hello/world"); assertThat(config.nameCanonicalNormalization).isEmpty(); assertThat(config.nameDisplayNormalization).isEmpty(); assertThat(config.pathEqualityUsesCanonicalForm).isFalse(); assertThat(config.blockSize).isEqualTo(8192); assertThat(config.maxSize).isEqualTo(4L * 1024 * 1024 * 1024); assertThat(config.maxCacheSize).isEqualTo(-1); assertThat(config.attributeViews).containsExactly("basic", "posix"); assertThat(config.attributeProviders).isEmpty(); assertThat(config.defaultAttributeValues).isEmpty(); }