private static void assertIllegalRoots(PathType type, String first, String... more) {
    try {
      Configuration.builder(type).setRoots(first, more); // wrong root
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }
Tests for {@link Configuration}, {@link Configuration.Builder} and file systems created from
them.

@author Colin Decker
jimfs/src/test/java/com/google/common/jimfs/ConfigurationTest.java