Make log4j-core available to Elasticsearch tests

Elasticsearch server requires log4j-core but we don't want the entire
module to have a test dependency on log4j-core as it already uses
Logback. This commit uses the modified class path runner to make
log4j-core available specifically to the Elasticsearch-related tests.

See gh-11166

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/data/elasticsearch/ElasticsearchRepositoriesAutoConfigurationTests.java

@@ -19,6 +19,7 @@ package org.springframework.boot.autoconfigure.data.elasticsearch;
 import org.elasticsearch.client.Client;
 import org.junit.After;
 import org.junit.Test;
+import org.junit.runner.RunWith;
 
 import org.springframework.boot.autoconfigure.TestAutoConfigurationPackage;
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
@@ -28,6 +29,8 @@ import org.springframework.boot.autoconfigure.data.elasticsearch.city.City;
 import org.springframework.boot.autoconfigure.data.elasticsearch.city.CityRepository;
 import org.springframework.boot.autoconfigure.data.empty.EmptyDataPackage;
 import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.boot.testsupport.runner.classpath.ClassPathOverrides;
+import org.springframework.boot.testsupport.runner.classpath.ModifiedClassPathRunner;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.elasticsearch.repository.config.EnableElasticsearchRepositories;
@@ -40,6 +43,8 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
+@RunWith(ModifiedClassPathRunner.class)
+@ClassPathOverrides("org.apache.logging.log4j:log4j-core:2.10.0")
 public class ElasticsearchRepositoriesAutoConfigurationTests {
 
 	private AnnotationConfigApplicationContext context;

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/elasticsearch/jest/JestAutoConfigurationTests.java

@@ -34,11 +34,14 @@ import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
 
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchNodeTemplate;
 import org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration;
 import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.boot.testsupport.runner.classpath.ClassPathOverrides;
+import org.springframework.boot.testsupport.runner.classpath.ModifiedClassPathRunner;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -53,6 +56,8 @@ import static org.mockito.Mockito.mock;
  * @author Stephane Nicoll
  * @author Andy Wilkinson
  */
+@RunWith(ModifiedClassPathRunner.class)
+@ClassPathOverrides("org.apache.logging.log4j:log4j-core:2.10.0")
 public class JestAutoConfigurationTests {
 
 	@Before