@Test
    void tlsEngineType() {
        final Server sb1 = Server.builder()
                                 .service("/example", (ctx, req) -> HttpResponse.of(HttpStatus.OK))
                                 .build();
        assertThat(sb1.config().defaultVirtualHost().tlsEngineType()).isEqualTo(TlsEngineType.OPENSSL);

        final Server sb2 = Server.builder()
                                 .tlsSelfSigned()
                                 .service("/example", (ctx, req) -> HttpResponse.of(HttpStatus.OK))
                                 .tlsEngineType(TlsEngineType.OPENSSL)
                                 .virtualHost("*.example1.com")
                                 .service("/example", (ctx, req) -> HttpResponse.of(HttpStatus.OK))
                                 .tlsSelfSigned()
                                 .tlsEngineType(TlsEngineType.JDK)
                                 .and()
                                 .virtualHost("*.example2.com")
                                 .service("/example", (ctx, req) -> HttpResponse.of(HttpStatus.OK))
                                 .tlsSelfSigned()
                                 .and()
                                 .virtualHost("*.example3.com")
                                 .service("/example", (ctx, req) -> HttpResponse.of(HttpStatus.OK))
                                 .and()
                                 .build();
        assertThat(sb2.config().defaultVirtualHost().tlsEngineType()).isEqualTo(TlsEngineType.OPENSSL);
        assertThat(sb2.config().findVirtualHost("*.example1.com", 8080).tlsEngineType())
                .isEqualTo(TlsEngineType.JDK);
        assertThat(sb2.config().findVirtualHost("*.example2.com", 8080).tlsEngineType())
                .isEqualTo(TlsEngineType.OPENSSL);
    }
Makes sure that {@link ServerBuilder#decorator(DecoratingHttpServiceFunction)} works at every service and
virtual hosts and {@link VirtualHostBuilder#decorator(DecoratingHttpServiceFunction)} works only at
its own services.
core/src/test/java/com/linecorp/armeria/server/ServerBuilderTest.java