Ensure that RestClientTest can be used without Jackson on the class path

Closes gh-7431

spring-boot-test-autoconfigure/pom.xml

@@ -128,6 +128,12 @@
 			<optional>true</optional>
 		</dependency>
 		<!-- Test -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot</artifactId>
+			<type>test-jar</type>
+			<scope>test</scope>
+		</dependency>
 		<dependency>
 			<groupId>ch.qos.logback</groupId>
 			<artifactId>logback-classic</artifactId>

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/client/RestClientExcludeFilter.java

@@ -21,8 +21,6 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
 
-import com.fasterxml.jackson.databind.Module;
-
 import org.springframework.boot.context.TypeExcludeFilter;
 import org.springframework.boot.jackson.JsonComponent;
 import org.springframework.boot.test.autoconfigure.filter.AnnotationCustomizableTypeExcludeFilter;
@@ -30,6 +28,7 @@ import org.springframework.context.annotation.ComponentScan.Filter;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
+import org.springframework.util.ClassUtils;
 
 /**
  * {@link TypeExcludeFilter} for {@link RestClientTest @RestClientTest}.
@@ -38,12 +37,24 @@ import org.springframework.core.type.classreading.MetadataReaderFactory;
  */
 class RestClientExcludeFilter extends AnnotationCustomizableTypeExcludeFilter {
 
+	private static final String DATABIND_MODULE_CLASS_NAME = "com.fasterxml.jackson.databind.Module";
+
 	private static final Set<Class<?>> DEFAULT_INCLUDES;
 
 	static {
 		Set<Class<?>> includes = new LinkedHashSet<Class<?>>();
-		includes.add(Module.class);
-		includes.add(JsonComponent.class);
+		if (ClassUtils.isPresent("com.fasterxml.jackson.databind.Module",
+				RestClientExcludeFilter.class.getClassLoader())) {
+			try {
+				includes.add(Class.forName(DATABIND_MODULE_CLASS_NAME, true,
+						RestClientExcludeFilter.class.getClassLoader()));
+			}
+			catch (ClassNotFoundException ex) {
+				throw new IllegalStateException(
+						"Failed to load " + DATABIND_MODULE_CLASS_NAME, ex);
+			}
+			includes.add(JsonComponent.class);
+		}
 		DEFAULT_INCLUDES = Collections.unmodifiableSet(includes);
 	}
 

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/web/client/RestClientTestWithoutJacksonIntegrationTests.java

+/*
+ * Copyright 2012-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.autoconfigure.web.client;
+
+import org.junit.Test;
+import org.junit.runner.JUnitCore;
+import org.junit.runner.Result;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.testutil.ClassPathExclusions;
+import org.springframework.boot.testutil.FilteredClassPathRunner;
+import org.springframework.util.ClassUtils;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link RestClientTest} without Jackson.
+ *
+ * @author Andy Wilkinson
+ */
+@RunWith(FilteredClassPathRunner.class)
+@ClassPathExclusions("jackson-*.jar")
+public class RestClientTestWithoutJacksonIntegrationTests {
+
+	@Test
+	public void restClientTestCanBeUsedWhenJacksonIsNotOnTheClassPath() {
+		assertThat(ClassUtils.isPresent("com.fasterxml.jackson.databind.Module",
+				getClass().getClassLoader())).isFalse();
+		Result result = JUnitCore
+				.runClasses(RestClientTestWithComponentIntegrationTests.class);
+		assertThat(result.getFailureCount()).isEqualTo(0);
+		assertThat(result.getRunCount()).isGreaterThan(0);
+	}
+
+}