Fix potential @AutoConfigureTestDatabase NPE

Protect against the situation where no DataSource beans can be found
at all.

Fixes gh-6897

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/orm/jpa/TestDatabaseAutoConfiguration.java

@@ -100,10 +100,12 @@ public class TestDatabaseAutoConfiguration {
 		private void process(BeanDefinitionRegistry registry,
 				ConfigurableListableBeanFactory beanFactory) {
 			BeanDefinitionHolder holder = getDataSourceBeanDefinition(beanFactory);
-			logger.info("Replacing '" + holder.getBeanName()
-					+ "' DataSource bean with embedded version");
-			registry.registerBeanDefinition(holder.getBeanName(),
-					createEmbeddedBeanDefinition());
+			if (holder != null) {
+				logger.info("Replacing '" + holder.getBeanName()
+						+ "' DataSource bean with embedded version");
+				registry.registerBeanDefinition(holder.getBeanName(),
+						createEmbeddedBeanDefinition());
+			}
 		}
 
 		private BeanDefinition createEmbeddedBeanDefinition() {
@@ -113,24 +115,23 @@ public class TestDatabaseAutoConfiguration {
 		private BeanDefinitionHolder getDataSourceBeanDefinition(
 				ConfigurableListableBeanFactory beanFactory) {
 			String[] beanNames = beanFactory.getBeanNamesForType(DataSource.class);
-			if (!ObjectUtils.isEmpty(beanNames)) {
-				if (beanNames.length == 1) {
-					String beanName = beanNames[0];
-					BeanDefinition beanDefinition = beanFactory
-							.getBeanDefinition(beanName);
+			if (ObjectUtils.isEmpty(beanNames)) {
+				logger.warn("No DataSource beans found, "
+						+ "embedded version will not be used");
+			}
+			if (beanNames.length == 1) {
+				String beanName = beanNames[0];
+				BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
+				return new BeanDefinitionHolder(beanDefinition, beanName);
+			}
+			for (String beanName : beanNames) {
+				BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
+				if (beanDefinition.isPrimary()) {
 					return new BeanDefinitionHolder(beanDefinition, beanName);
 				}
-				for (String beanName : beanNames) {
-					BeanDefinition beanDefinition = beanFactory
-							.getBeanDefinition(beanName);
-					if (beanDefinition.isPrimary()) {
-						return new BeanDefinitionHolder(beanDefinition, beanName);
-					}
-					logger.warn("No primary DataSource found, "
-							+ "embedded version will not be used");
-				}
-
 			}
+			logger.warn("No primary DataSource found, "
+					+ "embedded version will not be used");
 			return null;
 		}
 

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/orm/jpa/AutoConfigureTestDatabaseWithNoDatabaseIntegrationTests.java

@@ -0,0 +1,52 @@
+/*
+ * 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.orm.jpa;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.context.ApplicationContext;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link AutoConfigureTestDatabase} when there is no database.
+ *
+ * @author Phillip Webb
+ */
+@RunWith(SpringRunner.class)
+@AutoConfigureTestDatabase
+public class AutoConfigureTestDatabaseWithNoDatabaseIntegrationTests {
+
+	@Autowired
+	private ApplicationContext context;
+
+	@Test
+	public void testContextLoades() throws Exception {
+		// gh-6897
+		assertThat(this.context).isNotNull();
+	}
+
+	@SpringBootConfiguration
+	static class Config {
+
+	}
+
+}