8055953: [TESTBUG] Fix for 8055098 does not contain unit test

Add missing unit test.

Reviewed-by: tschatzl

hotspot/test/gc/whitebox/TestWBGC.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test TestWBGC
+ * @bug 8055098
+ * @summary Test verify that WB methods isObjectInOldGen and youngGC works correctly.
+ * @library /testlibrary /testlibrary/whitebox
+ * @build TestWBGC
+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run driver TestWBGC
+ */
+import com.oracle.java.testlibrary.*;
+import sun.hotspot.WhiteBox;
+
+public class TestWBGC {
+
+    public static void main(String args[]) throws Exception {
+        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
+                true,
+                "-Xbootclasspath/a:.",
+                "-XX:+UnlockDiagnosticVMOptions",
+                "-XX:+WhiteBoxAPI",
+                "-XX:MaxTenuringThreshold=1",
+                "-XX:+PrintGC",
+                GCYoungTest.class.getName());
+
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        System.out.println(output.getStdout());
+        output.shouldHaveExitValue(0);
+        output.shouldContain("WhiteBox Initiated Young GC");
+        output.shouldNotContain("Full");
+        // To be sure that we don't provoke Full GC additionaly to young
+    }
+
+    public static class GCYoungTest {
+        static WhiteBox wb = WhiteBox.getWhiteBox();
+        public static Object obj;
+
+        public static void main(String args[]) {
+            obj = new Object();
+            Asserts.assertFalse(wb.isObjectInOldGen(obj));
+            wb.youngGC();
+            wb.youngGC();
+            // 2 young GC is needed to promote object into OldGen
+            Asserts.assertTrue(wb.isObjectInOldGen(obj));
+        }
+    }
+}