can't inject `local.server.port` into a @Configuration so it can be wired into a @Component

So the short of my problem is, I’m trying to make a graphql client library, and test to see that it’s working. @LocalServerPort isn’t becoming available until @Test in Junit 5 in my project. I can’t quite repro this in a demo project, but I believe this project should work, as is

@SpringJUnitConfig
@SpringBootTest( webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT )
class ActuatorApplicationTest {

    @Autowired String url;

    @Test
    void port() {
        Assertions.assertNotNull( url );
    }

    @TestConfiguration
    static class Config {
        @Bean
        String url( @LocalServerPort int port ) {
            return "http://localhost:" + port;
        }
    }
}

This is my real code right now…

@Configuration
class ApolloConfig {

    @Bean
    @Profile( "!test" )
    static ApolloClient.Builder prodClient( @Value( "${phdb.endpoint}" ) String graphqlEndpoint ) {
        return ApolloClient.builder().serverUrl( graphqlEndpoint );
    }

    @Bean
    @Profile( "test" )
    static ApolloClient.Builder testClient(@Value( "${local.server.port}" ) int port ) {
        return ApolloClient.builder();
    }
}

failure is

 Unexpected exception during bean creation; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'local.server.port' in value "${local.server.port}"