PolicyTrie { static PolicyTrie fromPolicy(final Iterable<PolicyEntry> policy) { checkNotNull(policy, "policy to interpret"); final PolicyTrie prototype = new PolicyTrie(); policy.forEach(prototype::addPolicyEntry); return prototype; } private  PolicyTrie(); private  PolicyTrie(final GrantRevokeIndex grantRevokeIndex, final Map<JsonKey, PolicyTrie> children);   }
@SuppressWarnings("ConstantConditions") @Test public void tryToCreateInstanceFromNullPolicy() { assertThatExceptionOfType(NullPointerException.class) .isThrownBy(() -> PolicyTrie.fromPolicy(null)) .withMessage("The %s must not be null!", "policy to interpret") .withNoCause(); }