reactive-mail-server/backend/src/test/java/com/mailserver/smtp/MailRouterTest.java

package com.mailserver.smtp;

import com.mailserver.config.MailDomains;
import com.mailserver.delivery.OutboundQueue;
import com.mailserver.delivery.SmtpDeliveryClient;
import com.mailserver.domain.User;
import com.mailserver.repository.UserRepository;
import com.mailserver.service.DkimService;
import com.mailserver.service.LocalDelivery;
import com.mailserver.service.UserService;
import org.junit.jupiter.api.Test;
import reactor.core.publisher.Mono;

import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyBoolean;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

/** Mail trap (75.4): existing mailboxes keep their mail, everything else goes into the catch-all mailbox. */
class MailRouterTest {

    private final UserRepository users = mock(UserRepository.class);
    private final LocalDelivery localDelivery = mock(LocalDelivery.class);
    private final OutboundQueue queue = mock(OutboundQueue.class);
    private final SmtpDeliveryClient client = mock(SmtpDeliveryClient.class);

    private SmtpDeliveryClient.Mode mode = SmtpDeliveryClient.Mode.OFF;

    private static User user(String email, boolean trap) {
        User user = new User();
        user.setEmail(email);
        user.setTrap(trap);
        return user;
    }

    private MailRouter router(String catchAll) {
        when(users.existsByEmail(anyString())).thenReturn(Mono.just(false));
        when(users.existsByEmail("bob@mail.test")).thenReturn(Mono.just(true));
        when(users.findByEmail(anyString())).thenReturn(Mono.empty());
        when(users.findByEmail("bob@mail.test")).thenReturn(Mono.just(user("bob@mail.test", false)));
        when(users.findByEmail("staging@mail.test")).thenReturn(Mono.just(user("staging@mail.test", true)));
        when(client.mode()).thenReturn(mode);
        return new MailRouter(new MailDomains("mail.test", catchAll), users, mock(UserService.class), localDelivery,
                queue, mock(DkimService.class), client);
    }

    @Test
    void withoutCatchAllUnknownAndOutsideAddressesAreRefused() {
        MailRouter router = router("");

        assertThat(router.route("bob@mail.test", null)).isEqualTo(SmtpBackend.Route.LOCAL);
        assertThat(router.route("nobody@mail.test", null)).isEqualTo(SmtpBackend.Route.UNKNOWN_USER);
        assertThat(router.route("user@gmail.com", null)).isEqualTo(SmtpBackend.Route.RELAY_DENIED);
        assertThat(router.route("user@gmail.com", "bob@mail.test")).isEqualTo(SmtpBackend.Route.OUTBOUND_DISABLED);
    }

    @Test
    void catchAllTakesEverythingWithoutItsOwnMailboxButExistingMailboxesKeepTheirMail() throws Exception {
        MailRouter router = router("trap@mail.test");

        assertThat(router.route("nobody@mail.test", null)).isEqualTo(SmtpBackend.Route.LOCAL);
        assertThat(router.route("user@gmail.com", null)).isEqualTo(SmtpBackend.Route.LOCAL);
        assertThat(router.mailbox("bob@mail.test")).isEqualTo("bob@mail.test");
        assertThat(router.mailbox("user@gmail.com")).isEqualTo("trap@mail.test");

        router.accept(new SmtpBackend.Envelope("10.0.0.5", "staging", "no-reply@jambotron.com", null, List.of(
                new SmtpBackend.Recipient("user@gmail.com", SmtpBackend.Route.LOCAL),
                new SmtpBackend.Recipient("bob@mail.test", SmtpBackend.Route.LOCAL))), "Subject: hi\r\n\r\nbody".getBytes());

        verify(localDelivery).deliver(any(), eq("trap@mail.test"), eq("10.0.0.5"), eq("no-reply@jambotron.com"), anyBoolean());
        verify(localDelivery).deliver(any(), eq("bob@mail.test"), eq("10.0.0.5"), eq("no-reply@jambotron.com"), anyBoolean());
        verify(queue, never()).enqueue(any(), any(), any());
    }

    @Test
    void trapMailboxSendsNowhereOneCopyLandsInItsOwnInbox() throws Exception {
        mode = SmtpDeliveryClient.Mode.MX;
        MailRouter router = router("");

        // an ordinary mailbox still sends outside; the trap one keeps everything
        assertThat(router.route("user@gmail.com", "bob@mail.test")).isEqualTo(SmtpBackend.Route.OUTBOUND);
        assertThat(router.route("user@gmail.com", "staging@mail.test")).isEqualTo(SmtpBackend.Route.LOCAL);
        assertThat(router.route("nobody@mail.test", "Staging@Mail.test")).isEqualTo(SmtpBackend.Route.LOCAL);
        assertThat(router.route("bob@mail.test", "staging@mail.test")).isEqualTo(SmtpBackend.Route.LOCAL);

        router.accept(new SmtpBackend.Envelope("10.0.0.5", "staging", "staging@mail.test", "staging@mail.test", List.of(
                new SmtpBackend.Recipient("user@gmail.com", SmtpBackend.Route.LOCAL),
                new SmtpBackend.Recipient("bob@mail.test", SmtpBackend.Route.LOCAL))), "Subject: hi\r\n\r\nbody".getBytes());

        verify(localDelivery).deliver(any(), eq("staging@mail.test"), eq("10.0.0.5"), eq("staging@mail.test"), eq(true));
        verify(localDelivery, never()).deliver(any(), eq("bob@mail.test"), any(), any(), anyBoolean());
        verify(queue, never()).enqueue(any(), any(), any());
    }
}