Minimize and centralize assumptions about build output

Closes gh-15471

spring-boot-samples/spring-boot-sample-parent-context/src/test/java/sample/parent/consumer/SampleIntegrationParentApplicationTests.java

@@ -16,11 +16,12 @@
 
 package sample.parent.consumer;
 
+import java.io.File;
 import java.io.IOException;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
 import sample.parent.SampleParentContextApplication;
 import sample.parent.producer.ProducerApplication;
 
@@ -41,34 +42,41 @@ import static org.junit.Assert.fail;
  */
 public class SampleIntegrationParentApplicationTests {
 
-	private static ConfigurableApplicationContext context;
-
-	@BeforeClass
-	public static void start() {
-		context = SpringApplication.run(SampleParentContextApplication.class);
-	}
-
-	@AfterClass
-	public static void stop() {
-		if (context != null) {
-			context.close();
-		}
-	}
+	@Rule
+	public final TemporaryFolder temp = new TemporaryFolder();
 
 	@Test
 	public void testVanillaExchange() throws Exception {
-		SpringApplication.run(ProducerApplication.class, "World");
-		awaitOutputContaining("Hello World");
+		File inputDir = new File(this.temp.getRoot(), "input");
+		File outputDir = new File(this.temp.getRoot(), "output");
+		ConfigurableApplicationContext app = SpringApplication.run(
+				SampleParentContextApplication.class, "--service.input-dir=" + inputDir,
+				"--service.output-dir=" + outputDir);
+		try {
+			ConfigurableApplicationContext producer = SpringApplication.run(
+					ProducerApplication.class, "--service.input-dir=" + inputDir,
+					"--service.output-dir=" + outputDir, "World");
+			try {
+				awaitOutputContaining(outputDir, "Hello World");
+			}
+			finally {
+				producer.close();
+			}
+		}
+		finally {
+			app.close();
+		}
 	}
 
-	private void awaitOutputContaining(String requiredContents) throws Exception {
+	private void awaitOutputContaining(File outputDir, String requiredContents)
+			throws Exception {
 		long endTime = System.currentTimeMillis() + 30000;
 		String output = null;
 		while (System.currentTimeMillis() < endTime) {
-			Resource[] resources = findResources();
+			Resource[] resources = findResources(outputDir);
 			if (resources.length == 0) {
 				Thread.sleep(200);
-				resources = findResources();
+				resources = findResources(outputDir);
 			}
 			else {
 				output = readResources(resources);
@@ -85,10 +93,10 @@ public class SampleIntegrationParentApplicationTests {
 				+ "'. Output was '" + output + "'");
 	}
 
-	private Resource[] findResources() throws IOException {
+	private Resource[] findResources(File outputDir) throws IOException {
 		return ResourcePatternUtils
 				.getResourcePatternResolver(new DefaultResourceLoader())
-				.getResources("file:target/output/*.txt");
+				.getResources("file:" + outputDir.getAbsolutePath() + "/*.txt");
 	}
 
 	private String readResources(Resource[] resources) throws IOException {