@Test
  public void testAttributes_permissionsAreModifiable() {
    Set<PosixFilePermission> permissions = provider.readAttributes(file).permissions();
    permissions.add(PosixFilePermission.OWNER_EXECUTE);
    assertThat(permissions).isEqualTo(PosixFilePermissions.fromString("rwxr--r--"));
  }
Tests for {@link PosixAttributeProvider}.

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