Spring: test that the application's HTTP observations cover /acp

The endpoint is mounted on the application's own server and filter
chain, so Spring's ServerHttpObservationFilter records an
http.server.requests observation for an ACP request as for any other
request. A test with a TestObservationRegistry proves it.

Author: Mark Pollack

acp-spring-boot-autoconfigure/pom.xml

@@ -159,6 +159,17 @@
             <artifactId>spring-boot-starter-web</artifactId>
             <scope>test</scope>
         </dependency>
+        <!-- The application's HTTP observations cover /acp (AcpAgentHttpObservationTests) -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-micrometer-observation</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.micrometer</groupId>
+            <artifactId>micrometer-observation-test</artifactId>
+            <scope>test</scope>
+        </dependency>
         <!-- Framework security applies to /acp (AcpAgentHttpSecurityTests) -->
         <dependency>
             <groupId>org.springframework.boot</groupId>

acp-spring-boot-autoconfigure/src/test/java/com/agentclientprotocol/sdk/spring/boot/autoconfigure/agent/AcpAgentHttpObservationTests.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2025-2026 the original author or authors.
+ */
+
+package com.agentclientprotocol.sdk.spring.boot.autoconfigure.agent;
+
+import java.net.URI;
+
+import com.agentclientprotocol.sdk.spring.boot.autoconfigure.agent.AcpAgentHttpAutoConfigurationTests.EchoAgentConfiguration;
+import com.agentclientprotocol.sdk.test.http.HttpProbes;
+import io.micrometer.observation.tck.TestObservationRegistry;
+import io.micrometer.observation.tck.TestObservationRegistryAssert;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.server.LocalServerPort;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The application's own HTTP server observations cover {@code /acp}: the endpoint is mounted on
+ * the application's server and filter chain, so Spring's {@code ServerHttpObservationFilter}
+ * records an {@code http.server.requests} observation for an ACP request as for any other.
+ */
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, properties = "spring.acp.agent.transport.type=http")
+class AcpAgentHttpObservationTests {
+
+	@LocalServerPort
+	private int port;
+
+	@Autowired
+	private TestObservationRegistry observations;
+
+	@Test
+	void anAcpRequestIsObserved() throws Exception {
+		URI endpoint = URI.create("http://127.0.0.1:" + this.port + "/acp");
+		assertThat(HttpProbes.initialize(endpoint, null).statusCode()).isEqualTo(200);
+		TestObservationRegistryAssert.assertThat(this.observations)
+			.hasObservationWithNameEqualTo("http.server.requests")
+			.that()
+			.hasLowCardinalityKeyValue("method", "POST")
+			.hasLowCardinalityKeyValue("status", "200")
+			.hasBeenStopped();
+	}
+
+	@SpringBootConfiguration
+	@EnableAutoConfiguration
+	@Import(EchoAgentConfiguration.class)
+	static class ObservedApplication {
+
+		@Bean
+		TestObservationRegistry observationRegistry() {
+			return TestObservationRegistry.create();
+		}
+
+	}
+
+}