Polish contribution

Closes gh-8490

spring-boot-test/src/main/java/org/springframework/boot/test/rule/OutputCapture.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -91,6 +91,9 @@ public class OutputCapture implements TestRule {
 		this.copy = null;
 	}
 
+	/**
+	 * Discard all currently accumulated output.
+	 */
 	public void reset() {
 		this.copy.reset();
 	}

spring-boot-test/src/test/java/org/springframework/boot/test/rule/OutputCaptureTests.java

@@ -34,7 +34,6 @@ public class OutputCaptureTests {
 	@Test
 	public void toStringShouldReturnAllCapturedOutput() throws Exception {
 		System.out.println("Hello World");
-
 		assertThat(this.outputCapture.toString()).contains("Hello World");
 	}
 
@@ -43,7 +42,6 @@ public class OutputCaptureTests {
 		System.out.println("Hello");
 		this.outputCapture.reset();
 		System.out.println("World");
-
 		assertThat(this.outputCapture.toString()).doesNotContain("Hello")
 				.contains("World");
 	}