approval tests for java analog to csharp variant

Java/src/test/java/com/gildedrose/ApprovalTest.java

@@ -0,0 +1,28 @@
+package com.gildedrose;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+
+import org.approvaltests.Approvals;
+import org.approvaltests.reporters.DiffReporter;
+import org.approvaltests.reporters.UseReporter;
+import org.junit.jupiter.api.Test;
+
+@UseReporter(DiffReporter.class)
+public class ApprovalTest {
+
+	@Test
+	public void thirtyDays() {
+
+		ByteArrayOutputStream fakeoutput = new ByteArrayOutputStream();
+		System.setOut(new PrintStream(fakeoutput));
+		System.setIn(new ByteArrayInputStream("a\n".getBytes()));
+
+		Program.main();
+		String output = fakeoutput.toString();
+
+		Approvals.verify(output);
+	}
+
+}