No-op ResetMocksTestExecutionListener when Mockito is not present

Closes gh-11508

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/mock/mockito/ResetMocksTestExecutionListener.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -30,6 +30,7 @@ import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.test.context.TestContext;
 import org.springframework.test.context.TestExecutionListener;
 import org.springframework.test.context.support.AbstractTestExecutionListener;
+import org.springframework.util.ClassUtils;
 
 /**
  * {@link TestExecutionListener} to reset any mock beans that have been marked with a
@@ -40,15 +41,23 @@ import org.springframework.test.context.support.AbstractTestExecutionListener;
  */
 public class ResetMocksTestExecutionListener extends AbstractTestExecutionListener {
 
+	private static final boolean MOCKITO_IS_PRESENT = ClassUtils.isPresent(
+			"org.mockito.MockSettings",
+			ResetMocksTestExecutionListener.class.getClassLoader());
+
 	@Override
 	public void beforeTestMethod(TestContext testContext) throws Exception {
+		if (MOCKITO_IS_PRESENT) {
 			resetMocks(testContext.getApplicationContext(), MockReset.BEFORE);
 		}
+	}
 
 	@Override
 	public void afterTestMethod(TestContext testContext) throws Exception {
+		if (MOCKITO_IS_PRESENT) {
 			resetMocks(testContext.getApplicationContext(), MockReset.AFTER);
 		}
+	}
 
 	private void resetMocks(ApplicationContext applicationContext, MockReset reset) {
 		if (applicationContext instanceof ConfigurableApplicationContext) {

spring-boot-samples/spring-boot-sample-test-nomockito/src/test/java/sample/testnomockito/SampleTestNoMockitoApplicationTest.java → spring-boot-samples/spring-boot-sample-test-nomockito/src/test/java/sample/testnomockito/SampleTestNoMockitoApplicationTests.java

@@ -17,7 +17,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Madhura Bhave
  */
 @RunWith(SpringRunner.class)
-public class SampleTestNoMockitoApplicationTest {
+public class SampleTestNoMockitoApplicationTests {
 
 	// gh-7065