improve tests for RestTemplate (#11053)

Co-authored-by: Lauri Tulmin <tulmin@gmail.com>

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/RestTemplateBeanPostProcessorTest.java

@@ -1,67 +0,0 @@
-/*
- * Copyright The OpenTelemetry Authors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package io.opentelemetry.instrumentation.spring.autoconfigure.instrumentation.web;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import io.opentelemetry.api.OpenTelemetry;
-import org.junit.jupiter.api.DisplayName;
-import org.junit.jupiter.api.Test;
-import org.springframework.beans.factory.config.BeanPostProcessor;
-import org.springframework.beans.factory.support.DefaultListableBeanFactory;
-import org.springframework.http.client.ClientHttpRequestInterceptor;
-import org.springframework.web.client.RestTemplate;
-
-class RestTemplateBeanPostProcessorTest {
-  private static final DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
-
-  static {
-    beanFactory.registerSingleton("openTelemetry", OpenTelemetry.noop());
-  }
-
-  @Test
-  @DisplayName("when processed bean is not of type RestTemplate should return object")
-  void returnsObject() {
-    BeanPostProcessor underTest =
-        new RestTemplateBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
-
-    assertThat(underTest.postProcessAfterInitialization(new Object(), "testObject"))
-        .isExactlyInstanceOf(Object.class);
-  }
-
-  @Test
-  @DisplayName("when processed bean is of type RestTemplate should return RestTemplate")
-  void returnsRestTemplate() {
-    BeanPostProcessor underTest =
-        new RestTemplateBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
-
-    assertThat(underTest.postProcessAfterInitialization(new RestTemplate(), "testRestTemplate"))
-        .isInstanceOf(RestTemplate.class);
-  }
-
-  @Test
-  @DisplayName("when processed bean is of type RestTemplate should add ONE RestTemplateInterceptor")
-  void addsRestTemplateInterceptor() {
-    BeanPostProcessor underTest =
-        new RestTemplateBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
-
-    RestTemplate restTemplate = new RestTemplate();
-
-    underTest.postProcessAfterInitialization(restTemplate, "testRestTemplate");
-    underTest.postProcessAfterInitialization(restTemplate, "testRestTemplate");
-    underTest.postProcessAfterInitialization(restTemplate, "testRestTemplate");
-
-    assertThat(
-            restTemplate.getInterceptors().stream()
-                .filter(RestTemplateBeanPostProcessorTest::isOtelInstrumentationInterceptor)
-                .count())
-        .isEqualTo(1);
-  }
-
-  private static boolean isOtelInstrumentationInterceptor(ClientHttpRequestInterceptor rti) {
-    return rti.getClass().getName().startsWith("io.opentelemetry.instrumentation");
-  }
-}

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/SpringWebInstrumentationAutoConfigurationTest.java

@@ -11,26 +11,47 @@ import io.opentelemetry.api.OpenTelemetry;
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.web.client.RestTemplate;
 
 class SpringWebInstrumentationAutoConfigurationTest {
 
   private final ApplicationContextRunner contextRunner =
       new ApplicationContextRunner()
           .withBean(OpenTelemetry.class, OpenTelemetry::noop)
+          .withBean(RestTemplate.class, RestTemplate::new)
           .withConfiguration(
               AutoConfigurations.of(SpringWebInstrumentationAutoConfiguration.class));
 
+  /**
+   * Tests that users create {@link RestTemplate} bean is instrumented.
+   *
+   * <pre>{@code
+   * @Bean public RestTemplate restTemplate() {
+   *     return new RestTemplate();
+   * }
+   * }</pre>
+   */
   @Test
   void instrumentationEnabled() {
     contextRunner
         .withPropertyValues("otel.instrumentation.spring-web.enabled=true")
         .run(
-            context ->
+            context -> {
               assertThat(
                       context.getBean(
-                            "otelRestTemplateBeanPostProcessor",
+                          "otelRestTemplateBeanPostProcessor", RestTemplateBeanPostProcessor.class))
-                            RestTemplateBeanPostProcessor.class))
+                  .isNotNull();
-                    .isNotNull());
+
+              assertThat(
+                      context.getBean(RestTemplate.class).getInterceptors().stream()
+                          .filter(
+                              rti ->
+                                  rti.getClass()
+                                      .getName()
+                                      .startsWith("io.opentelemetry.instrumentation"))
+                          .count())
+                  .isEqualTo(1);
+            });
   }
 
   @Test