Remove reflection to make tests more stable

See spring-projectsgh-30156

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/TracingAutoConfigurationTests.java

@@ -16,31 +16,29 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
-import java.lang.reflect.Method;
-import java.util.Collection;
+import java.util.ArrayList;
 import java.util.List;
 
 import io.micrometer.core.instrument.observation.MeterObservationHandler;
+import io.micrometer.core.instrument.observation.Observation;
 import io.micrometer.core.instrument.observation.Observation.Context;
 import io.micrometer.core.instrument.observation.ObservationHandler;
 import io.micrometer.core.instrument.observation.ObservationHandler.AllMatchingCompositeObservationHandler;
-import io.micrometer.core.instrument.observation.ObservationHandler.CompositeObservationHandler;
 import io.micrometer.core.instrument.observation.ObservationHandler.FirstMatchingCompositeObservationHandler;
 import io.micrometer.core.instrument.observation.ObservationRegistry;
-import io.micrometer.core.instrument.observation.ObservationRegistry.ObservationConfig;
-import io.micrometer.core.instrument.observation.TimerObservationHandler;
 import io.micrometer.tracing.Tracer;
-import io.micrometer.tracing.handler.DefaultTracingObservationHandler;
+import io.micrometer.tracing.handler.TracingObservationHandler;
 import org.junit.jupiter.api.Test;
+import org.mockito.Answers;
 import org.mockito.Mockito;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.test.MetricsRun;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
 import org.springframework.core.annotation.Order;
-import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -55,55 +53,51 @@ class TracingAutoConfigurationTests {
 			.withConfiguration(AutoConfigurations.of(TracingAutoConfiguration.class));
 
 	@Test
-	@SuppressWarnings("rawtypes")
 	void autoConfiguresObservationHandler() {
 		this.contextRunner.withUserConfiguration(ObservationHandlers.class).run((context) -> {
 			ObservationRegistry observationRegistry = context.getBean(ObservationRegistry.class);
-			List<ObservationHandler<?>> handlers = getObservationHandlers(observationRegistry);
-			assertThat(handlers).hasSize(6);
-			assertThat(handlers.get(0)).isInstanceOf(TimerObservationHandler.class);
-			assertThat(handlers.get(1)).isInstanceOf(CustomObservationHandler.class);
-			assertThat(handlers.get(2)).isInstanceOf(FirstMatchingCompositeObservationHandler.class);
-			assertThat(handlers.get(3)).isInstanceOf(AllMatchingCompositeObservationHandler.class);
-			// CustomMeterObservationHandlers get wrapped into a
-			// FirstMatchingCompositeObservationHandler
-			assertThat(handlers.get(4)).isInstanceOf(FirstMatchingCompositeObservationHandler.class);
-			List<ObservationHandler> containedHandlers = ((CompositeObservationHandler) handlers.get(4)).getHandlers();
-			assertThat(containedHandlers).hasSize(2);
-			assertThat(containedHandlers.get(0)).isInstanceOf(CustomMeterObservationHandler.class);
-			assertThat(containedHandlers.get(1)).isInstanceOf(CustomMeterObservationHandler.class);
-			assertThat(handlers.get(4)).isInstanceOf(FirstMatchingCompositeObservationHandler.class);
-			// DefaultTracingObservationHandler get wrapped into a
-			// FirstMatchingCompositeObservationHandler
-			containedHandlers = ((CompositeObservationHandler) handlers.get(5)).getHandlers();
-			assertThat(containedHandlers).hasSize(2);
-			assertThat(containedHandlers.get(0)).isInstanceOf(DefaultTracingObservationHandler.class);
-			assertThat(containedHandlers.get(1)).isInstanceOf(DefaultTracingObservationHandler.class);
-
+			List<ObservationHandler<?>> handlers = context.getBean(CalledHandlers.class).getCalledHandlers();
+			Observation.start("test-observation", observationRegistry);
+			assertThat(handlers).hasSize(3);
+			// Regular handlers are registered first
+			assertThat(handlers.get(0)).isInstanceOf(CustomObservationHandler.class);
+			// Multiple MeterObservationHandler are wrapped in
+			// FirstMatchingCompositeObservationHandler, which calls only the first one
+			assertThat(handlers.get(1)).isInstanceOf(CustomMeterObservationHandler.class);
+			assertThat(((CustomMeterObservationHandler) handlers.get(1)).getName())
+					.isEqualTo("customMeterObservationHandler1");
+			// Multiple TracingObservationHandler are wrapped in
+			// FirstMatchingCompositeObservationHandler, which calls only the first one
+			assertThat(handlers.get(2)).isInstanceOf(CustomTracingObservationHandler.class);
+			assertThat(((CustomTracingObservationHandler) handlers.get(2)).getName())
+					.isEqualTo("customTracingHandler1");
 		});
 	}
 
-	@SuppressWarnings("unchecked")
-	private List<ObservationHandler<?>> getObservationHandlers(ObservationRegistry registry) {
-		Method method = ReflectionUtils.findMethod(ObservationConfig.class, "getObservationHandlers");
-		ReflectionUtils.makeAccessible(method);
-		return List.copyOf(
-				(Collection<ObservationHandler<?>>) ReflectionUtils.invokeMethod(method, registry.observationConfig()));
+	@Configuration(proxyBeanMethods = false)
+	static class CalledHandlersConfiguration {
+
+		@Bean
+		CalledHandlers calledHandlers() {
+			return new CalledHandlers();
+		}
+
 	}
 
 	@Configuration(proxyBeanMethods = false)
+	@Import(CalledHandlersConfiguration.class)
 	static class ObservationHandlers {
 
 		@Bean
 		@Order(6)
-		DefaultTracingObservationHandler customTracingHandler2() {
-			return new DefaultTracingObservationHandler(Mockito.mock(Tracer.class));
+		CustomTracingObservationHandler customTracingHandler2(CalledHandlers calledHandlers) {
+			return new CustomTracingObservationHandler("customTracingHandler2", calledHandlers);
 		}
 
 		@Bean
 		@Order(5)
-		DefaultTracingObservationHandler customTracingHandler1() {
-			return new DefaultTracingObservationHandler(Mockito.mock(Tracer.class));
+		CustomTracingObservationHandler customTracingHandler1(CalledHandlers calledHandlers) {
+			return new CustomTracingObservationHandler("customTracingHandler1", calledHandlers);
 		}
 
 		@Bean
@@ -120,25 +114,84 @@ FirstMatchingCompositeObservationHandler customFirstMatchingCompositeObservation
 
 		@Bean
 		@Order(2)
-		ObservationHandler<Context> customObservationHandler() {
-			return new CustomObservationHandler();
+		ObservationHandler<Context> customObservationHandler(CalledHandlers calledHandlers) {
+			return new CustomObservationHandler(calledHandlers);
 		}
 
 		@Bean
 		@Order(1)
-		MeterObservationHandler<Context> customMeterObservationHandler2() {
-			return new CustomMeterObservationHandler();
+		MeterObservationHandler<Context> customMeterObservationHandler2(CalledHandlers calledHandlers) {
+			return new CustomMeterObservationHandler("customMeterObservationHandler2", calledHandlers);
 		}
 
 		@Bean
 		@Order(0)
-		MeterObservationHandler<Context> customMeterObservationHandler1() {
-			return new CustomMeterObservationHandler();
+		MeterObservationHandler<Context> customMeterObservationHandler1(CalledHandlers calledHandlers) {
+			return new CustomMeterObservationHandler("customMeterObservationHandler1", calledHandlers);
+		}
+
+	}
+
+	private static class CalledHandlers {
+
+		private final List<ObservationHandler<?>> calledHandlers = new ArrayList<>();
+
+		void onCalled(ObservationHandler<?> handler) {
+			this.calledHandlers.add(handler);
+		}
+
+		List<ObservationHandler<?>> getCalledHandlers() {
+			return this.calledHandlers;
+		}
+
+	}
+
+	private static class CustomTracingObservationHandler implements TracingObservationHandler<Context> {
+
+		private final Tracer tracer = Mockito.mock(Tracer.class, Answers.RETURNS_MOCKS);
+
+		private final String name;
+
+		private final CalledHandlers calledHandlers;
+
+		CustomTracingObservationHandler(String name, CalledHandlers calledHandlers) {
+			this.name = name;
+			this.calledHandlers = calledHandlers;
+		}
+
+		String getName() {
+			return this.name;
+		}
+
+		@Override
+		public Tracer getTracer() {
+			return this.tracer;
+		}
+
+		@Override
+		public void onStart(Context context) {
+			this.calledHandlers.onCalled(this);
+		}
+
+		@Override
+		public boolean supportsContext(Context context) {
+			return true;
 		}
 
 	}
 
-	static class CustomObservationHandler implements ObservationHandler<Context> {
+	private static class CustomObservationHandler implements ObservationHandler<Context> {
+
+		private final CalledHandlers calledHandlers;
+
+		CustomObservationHandler(CalledHandlers calledHandlers) {
+			this.calledHandlers = calledHandlers;
+		}
+
+		@Override
+		public void onStart(Context context) {
+			this.calledHandlers.onCalled(this);
+		}
 
 		@Override
 		public boolean supportsContext(Context context) {
@@ -147,7 +200,25 @@ public boolean supportsContext(Context context) {
 
 	}
 
-	static class CustomMeterObservationHandler implements MeterObservationHandler<Context> {
+	private static class CustomMeterObservationHandler implements MeterObservationHandler<Context> {
+
+		private final CalledHandlers calledHandlers;
+
+		private final String name;
+
+		CustomMeterObservationHandler(String name, CalledHandlers calledHandlers) {
+			this.name = name;
+			this.calledHandlers = calledHandlers;
+		}
+
+		String getName() {
+			return this.name;
+		}
+
+		@Override
+		public void onStart(Context context) {
+			this.calledHandlers.onCalled(this);
+		}
 
 		@Override
 		public boolean supportsContext(Context context) {