Add OutputCapture test class

spring-boot-samples/spring-boot-sample-simple/src/test/java/org/springframework/boot/sample/simple/SampleSimpleApplicationTests.java

@@ -16,13 +16,11 @@
 
 package org.springframework.boot.sample.simple;
 
-import java.io.ByteArrayOutputStream;
-import java.io.PrintStream;
-
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
-import org.springframework.boot.sample.simple.SampleSimpleApplication;
+import org.springframework.boot.OutputCapture;
 
 import static org.junit.Assert.assertTrue;
 
@@ -34,17 +32,13 @@ import static org.junit.Assert.assertTrue;
  */
 public class SampleSimpleApplicationTests {
 
-	private PrintStream savedOutput;
-
-	private ByteArrayOutputStream output;
+	@Rule
+	public OutputCapture outputCapture = new OutputCapture();
 
 	private String profiles;
 
 	@Before
 	public void init() {
-		this.savedOutput = System.out;
-		this.output = new ByteArrayOutputStream();
-		System.setOut(new PrintStream(this.output));
 		this.profiles = System.getProperty("spring.profiles.active");
 	}
 
@@ -56,24 +50,19 @@ public class SampleSimpleApplicationTests {
 		else {
 			System.clearProperty("spring.profiles.active");
 		}
-		System.setOut(this.savedOutput);
-	}
-
-	private String getOutput() {
-		return this.output.toString();
 	}
 
 	@Test
 	public void testDefaultSettings() throws Exception {
 		SampleSimpleApplication.main(new String[0]);
-		String output = getOutput();
+		String output = this.outputCapture.toString();
 		assertTrue("Wrong output: " + output, output.contains("Hello Phil"));
 	}
 
 	@Test
 	public void testCommandLineOverrides() throws Exception {
 		SampleSimpleApplication.main(new String[] { "--name=Gordon" });
-		String output = getOutput();
+		String output = this.outputCapture.toString();
 		assertTrue("Wrong output: " + output, output.contains("Hello Gordon"));
 	}