@Override
        public HttpResponse convertResponse(ServiceRequestContext ctx,
                                            ResponseHeaders headers,
                                            @Nullable Object result,
                                            HttpHeaders trailers) throws Exception {
            if (result instanceof String) {
                return HttpResponse.of(HttpStatus.OK,
                                       MediaType.ANY_TEXT_TYPE,
                                       HttpData.ofUtf8(result.toString()),
                                       trailers);
            }
            return ResponseConverterFunction.fallthrough();
        }
This uses {@link ArmeriaAutoConfiguration} for integration tests.
application-autoConfTest.yml will be loaded with minimal settings to make it work.
spring/boot3-autoconfigure/src/test/java/com/linecorp/armeria/spring/ArmeriaAutoConfigurationTest.java