Add test for protobuf scrape

Author: shakuzen

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/export/prometheus/PrometheusScrapeEndpointIntegrationTests.java

@@ -21,6 +21,7 @@
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.prometheusmetrics.PrometheusMeterRegistry;
 import io.prometheus.metrics.expositionformats.OpenMetricsTextFormatWriter;
+import io.prometheus.metrics.expositionformats.PrometheusProtobufWriter;
 import io.prometheus.metrics.expositionformats.PrometheusTextFormatWriter;
 import io.prometheus.metrics.model.registry.PrometheusRegistry;
 
@@ -120,6 +121,21 @@ void scrapeWithIncludedNames(WebTestClient client) {
 				.doesNotContain("counter3_total"));
 	}
 
+	@WebEndpointTest
+	void scrapeCanProducePrometheusProtobuf(WebTestClient client) {
+		MediaType prometheusProtobuf = MediaType.parseMediaType(PrometheusProtobufWriter.CONTENT_TYPE);
+		client.get()
+			.uri("/actuator/prometheus")
+			.accept(prometheusProtobuf)
+			.exchange()
+			.expectStatus()
+			.isOk()
+			.expectHeader()
+			.contentType(prometheusProtobuf)
+			.expectBody(byte[].class)
+			.value((body) -> assertThat(body).isNotEmpty());
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class TestConfiguration {