[TEST] customize test global cluster for REST tests only if REST tests are enabled

Closes elastic/elasticsearch#107

Original commit: elastic/x-pack-elasticsearch@55eea46460

src/test/java/org/elasticsearch/test/ShieldRestTests.java

@@ -5,8 +5,10 @@
  */
 package org.elasticsearch.test;
 
+import com.carrotsearch.randomizedtesting.RandomizedTest;
 import com.carrotsearch.randomizedtesting.SysGlobals;
 import com.carrotsearch.randomizedtesting.annotations.Name;
+import com.carrotsearch.randomizedtesting.annotations.TestGroup;
 import com.google.common.base.Charsets;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.io.Streams;
@@ -57,6 +59,20 @@ public class ShieldRestTests extends ElasticsearchRestTests {
             "    '.*': ALL\n";
 
     static {
+
+        TestGroup testGroup = Rest.class.getAnnotation(TestGroup.class);
+        String sysProperty = TestGroup.Utilities.getSysProperty(Rest.class);
+        boolean enabled;
+        try {
+            enabled = RandomizedTest.systemPropertyAsBoolean(sysProperty, testGroup.enabled());
+        } catch (IllegalArgumentException e) {
+            // Ignore malformed system property, disable the group if malformed though.
+            enabled = false;
+        }
+
+        //customize the global cluster only if rest tests are enabled
+        //not perfect but good enough as REST tests are supposed to be run only separately on CI
+        if (enabled) {
             final byte[] key;
             try {
                 key = InternalKeyService.generateKey();
@@ -139,6 +155,7 @@ public class ShieldRestTests extends ElasticsearchRestTests {
                 }
             };
         }
+    }
 
     @ClassRule
     public static TemporaryFolder tmpFolder = new TemporaryFolder();