@Test
  @SuppressWarnings("deprecation") // This is a test for the deprecated function
  public void testGetVersion() throws Exception {
    assertThat(manager.getVersion()).isEqualTo(0);
  }
We test newKeyData directly because PrfBasedDeriverKeyManager has its own implementation.
java_src/src/test/java/com/google/crypto/tink/keyderivation/internal/PrfBasedDeriverKeyManagerTest.java