Merge pull request #44789 from nosan

* pr/44789:
  Add tests for OtlpTracingAutoConfiguration

Closes gh-44789

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/build.gradle

@@ -139,6 +139,7 @@ dependencies {
 	testImplementation(project(":spring-boot-project:spring-boot-tools:spring-boot-test-support"))
 	testImplementation(testFixtures(project(":spring-boot-project:spring-boot")))
 	testImplementation("io.micrometer:micrometer-observation-test")
+	testImplementation("io.opentelemetry:opentelemetry-exporter-common")
 	testImplementation("io.projectreactor:reactor-test")
 	testImplementation("io.prometheus:prometheus-metrics-exposition-formats")
 	testImplementation("io.r2dbc:r2dbc-h2")

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/otlp/OtlpTracingAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,15 @@
 
 package org.springframework.boot.actuate.autoconfigure.tracing.otlp;
 
+import java.util.List;
+import java.util.function.Supplier;
+
+import io.opentelemetry.exporter.internal.compression.GzipCompressor;
 import io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporter;
 import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporter;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 import okhttp3.HttpUrl;
+import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.actuate.autoconfigure.tracing.otlp.OtlpTracingConfigurations.ConnectionDetails.PropertiesOtlpTracingConnectionDetails;
@@ -64,6 +69,27 @@ void shouldSupplyBeans() {
 				.hasSingleBean(SpanExporter.class));
 	}
 
+	@Test
+	void shouldCustomizeHttpTransportWithProperties() {
+		this.contextRunner
+			.withPropertyValues("management.otlp.tracing.endpoint=http://localhost:4317/v1/traces",
+					"management.otlp.tracing.timeout=10m", "management.otlp.tracing.connect-timeout=20m",
+					"management.otlp.tracing.compression=GZIP", "management.otlp.tracing.headers.spring=boot")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(OtlpHttpSpanExporter.class).hasSingleBean(SpanExporter.class);
+				OtlpHttpSpanExporter exporter = context.getBean(OtlpHttpSpanExporter.class);
+				assertThat(exporter).extracting("delegate.httpSender.client")
+					.hasFieldOrPropertyWithValue("connectTimeoutMillis", 1200000)
+					.hasFieldOrPropertyWithValue("callTimeoutMillis", 600000);
+				assertThat(exporter).extracting("delegate.httpSender.compressor").isInstanceOf(GzipCompressor.class);
+				assertThat(exporter).extracting("delegate.httpSender.headerSupplier")
+					.asInstanceOf(InstanceOfAssertFactories.type(Supplier.class))
+					.satisfies((headerSupplier) -> assertThat(headerSupplier.get())
+						.asInstanceOf(InstanceOfAssertFactories.map(String.class, List.class))
+						.containsEntry("spring", List.of("boot")));
+			});
+	}
+
 	@Test
 	void shouldSupplyBeansIfGrpcTransportIsEnabled() {
 		this.contextRunner
@@ -73,6 +99,28 @@ void shouldSupplyBeansIfGrpcTransportIsEnabled() {
 				.hasSingleBean(SpanExporter.class));
 	}
 
+	@Test
+	void shouldCustomizeGrpcTransportWithProperties() {
+		this.contextRunner
+			.withPropertyValues("management.otlp.tracing.endpoint=http://localhost:4317/v1/traces",
+					"management.otlp.tracing.transport=grpc", "management.otlp.tracing.timeout=10m",
+					"management.otlp.tracing.connect-timeout=20m", "management.otlp.tracing.compression=GZIP",
+					"management.otlp.tracing.headers.spring=boot")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(OtlpGrpcSpanExporter.class).hasSingleBean(SpanExporter.class);
+				OtlpGrpcSpanExporter exporter = context.getBean(OtlpGrpcSpanExporter.class);
+				assertThat(exporter).extracting("delegate.grpcSender.client")
+					.hasFieldOrPropertyWithValue("connectTimeoutMillis", 1200000)
+					.hasFieldOrPropertyWithValue("callTimeoutMillis", 600000);
+				assertThat(exporter).extracting("delegate.grpcSender.compressor").isInstanceOf(GzipCompressor.class);
+				assertThat(exporter).extracting("delegate.grpcSender.headersSupplier")
+					.asInstanceOf(InstanceOfAssertFactories.type(Supplier.class))
+					.satisfies((headerSupplier) -> assertThat(headerSupplier.get())
+						.asInstanceOf(InstanceOfAssertFactories.map(String.class, List.class))
+						.containsEntry("spring", List.of("boot")));
+			});
+	}
+
 	@Test
 	void shouldNotSupplyBeansIfGlobalTracingIsDisabled() {
 		this.contextRunner.withPropertyValues("management.tracing.enabled=false")