@Test
  public void test_parseParametersWithLegacyFallback_testFallback() throws Exception {
    MutableSerializationRegistry registry = new MutableSerializationRegistry();
    ProtoParametersSerialization protoParameters =
        ProtoParametersSerialization.create(
            "typeUrlForTesting73107", OutputPrefixType.TINK, TestProto.getDefaultInstance());
    Parameters parameters = registry.parseParametersWithLegacyFallback(protoParameters);
    assertThat(parameters).isInstanceOf(LegacyProtoParameters.class);
    LegacyProtoParameters legacyProtoParameters = (LegacyProtoParameters) parameters;
    assertThat(legacyProtoParameters.getSerialization().getKeyTemplate().getTypeUrl())
        .isEqualTo("typeUrlForTesting73107");
  }
Tests for {@link MutableSerializationRegistry}.

<p>We repeat the main tests in SerializationRegistryTest. There really shouldn't be both classes,
but currently this is what we need, and the other is what we should have.
java_src/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryTest.java