Polish contribution

Add missing test

Closes gh-7193

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/orm/jpa/TestDatabaseAutoConfigurationTests.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.orm.jpa;
+
+import javax.sql.DataSource;
+
+import org.junit.After;
+import org.junit.Test;
+
+import org.springframework.boot.test.util.EnvironmentTestUtils;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link TestDatabaseAutoConfiguration}.
+ *
+ * @author Stephane Nicoll
+ */
+public class TestDatabaseAutoConfigurationTests {
+
+	private ConfigurableApplicationContext context;
+
+	@After
+	public void closeContext() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void replaceWithNoDataSourceAvailable() {
+		load(null);
+		assertThat(this.context.getBeansOfType(DataSource.class)).isEmpty();
+	}
+
+	public void load(Class<?> config, String... environment) {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		if (config != null) {
+			ctx.register(config);
+		}
+		ctx.register(TestDatabaseAutoConfiguration.class);
+		EnvironmentTestUtils.addEnvironment(ctx, environment);
+		ctx.refresh();
+		this.context = ctx;
+	}
+
+}