Add ConfigFileApplicationContextInitializer

Reintroduce ConfigFileApplicationContextInitializer for tests that
wish to reuse 'application.properties' configuration.

Fixes spring-projectsgh-344

Author: Phillip Webb

spring-boot/src/main/java/org/springframework/boot/context/config/ConfigFileApplicationListener.java

@@ -131,6 +131,20 @@ private void onApplicationEnvironmentPreparedEvent(
 
 	private void onApplicationEnvironmentPreparedEvent(
 			ConfigurableEnvironment environment, SpringApplication application) {
+		addProperySources(environment);
+		bindToSpringApplication(environment, application);
+	}
+
+	private void onApplicationPreparedEvent(ApplicationPreparedEvent event) {
+		addPostProcessors(event.getApplicationContext());
+	}
+
+	/**
+	 * Add config file property sources to the specified environment.
+	 * @param environment the environment to add source to
+	 * @see #addPostProcessors(ConfigurableApplicationContext)
+	 */
+	protected void addProperySources(ConfigurableEnvironment environment) {
 		RandomValuePropertySource.addToEnvironment(environment);
 		try {
 			PropertySource<?> defaultProperties = environment.getPropertySources()
@@ -143,18 +157,25 @@ private void onApplicationEnvironmentPreparedEvent(
 		catch (IOException ex) {
 			throw new IllegalStateException("Unable to load configuration files", ex);
 		}
-		bindToSpringApplication(application, environment);
 	}
 
-	private void bindToSpringApplication(SpringApplication application,
-			ConfigurableEnvironment environment) {
+	/**
+	 * Bind the environment to the {@link SpringApplication}.
+	 * @param environment the environment to bind
+	 * @param application the application to bind to
+	 */
+	protected void bindToSpringApplication(ConfigurableEnvironment environment,
+			SpringApplication application) {
 		RelaxedDataBinder binder = new RelaxedDataBinder(application, "spring.main");
 		binder.setConversionService(this.conversionService);
 		binder.bind(new PropertySourcesPropertyValues(environment.getPropertySources()));
 	}
 
-	private void onApplicationPreparedEvent(ApplicationPreparedEvent event) {
-		ConfigurableApplicationContext context = event.getApplicationContext();
+	/**
+	 * Add appropriate post-processors to post-configure the property-sources.
+	 * @param context the context to configure
+	 */
+	protected void addPostProcessors(ConfigurableApplicationContext context) {
 		context.addBeanFactoryPostProcessor(new PropertySourceOrderingPostProcessor(
 				context));
 	}

spring-boot/src/main/java/org/springframework/boot/test/ConfigFileApplicationContextInitializer.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2014 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;
+
+import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.test.context.ContextConfiguration;
+
+/**
+ * {@link ApplicationContextInitializer} that can be used with the
+ * {@link ContextConfiguration#initializers()} to trigger loading of
+ * {@literal application.properties}.
+ * 
+ * @author Phillip Webb
+ * @see ConfigFileApplicationListener
+ */
+public class ConfigFileApplicationContextInitializer implements
+		ApplicationContextInitializer<ConfigurableApplicationContext> {
+
+	@Override
+	public void initialize(final ConfigurableApplicationContext applicationContext) {
+		new ConfigFileApplicationListener() {
+			public void apply() {
+				addProperySources(applicationContext.getEnvironment());
+				addPostProcessors(applicationContext);
+			}
+		}.apply();
+	}
+
+}

spring-boot/src/test/java/org/springframework/boot/test/ConfigFileApplicationContextInitializerTests.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012-2014 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;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.Environment;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link ConfigFileApplicationContextInitializer}.
+ * 
+ * @author Phillip Webb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = ConfigFileApplicationContextInitializerTests.Config.class, initializers = ConfigFileApplicationContextInitializer.class)
+public class ConfigFileApplicationContextInitializerTests {
+
+	@Autowired
+	private Environment environment;
+
+	@Test
+	public void test() {
+		assertThat(this.environment.getProperty("foo"), equalTo("bucket"));
+	}
+
+	@Configuration
+	public static class Config {
+
+	}
+}