[TEST] remove redundant tests and move to different suite

Some of the test for meta data are redundant. Also, since they
somewhat test service disruptions (start master with empty
data folder) we might move them to DiscoveryWithServiceDisruptionsTests.
Also, this commit adds a test for
elastic#11665

core/src/main/java/org/elasticsearch/cluster/ClusterChangedEvent.java

@@ -110,8 +110,11 @@ public List<String> indicesDeleted() {
         // is actually supposed to be deleted or imported as dangling instead. for example a new master might not have
         // the index in its cluster state because it was started with an empty data folder and in this case we want to
         // import as dangling. we check here for new master too to be on the safe side in this case.
-        // norelease because we are not sure this is actually a good solution
-        // See discussion on https://github.com/elastic/elasticsearch/pull/9952
+        // This means that under certain conditions deleted indices might be reimported if a master fails while the deletion
+        // request is issued and a node receives the cluster state that would trigger the deletion from the new master.
+        // See test MetaDataWriteDataNodesTests.testIndicesDeleted()
+        // See discussion on https://github.com/elastic/elasticsearch/pull/9952 and
+        // https://github.com/elastic/elasticsearch/issues/11665
         if (hasNewMaster() || previousState == null) {
             return ImmutableList.of();
         }

core/src/test/java/org/elasticsearch/discovery/DiscoveryWithServiceDisruptionsTests.java

@@ -56,6 +56,7 @@
 import org.elasticsearch.test.transport.MockTransportService;
 import org.elasticsearch.transport.*;
 import org.junit.Before;
+import org.junit.Ignore;
 import org.junit.Test;
 
 import java.io.IOException;
@@ -65,6 +66,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
+import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.test.ElasticsearchIntegrationTest.ClusterScope;
 import static org.elasticsearch.test.ElasticsearchIntegrationTest.Scope;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
@@ -237,7 +239,9 @@ public void failWithMinimumMasterNodesConfigured() throws Exception {
     }
 
 
-    /** Verify that nodes fault detection works after master (re) election */
+    /**
+     * Verify that nodes fault detection works after master (re) election
+     */
     @Test
     public void testNodesFDAfterMasterReelection() throws Exception {
         startCluster(4);
@@ -414,7 +418,7 @@ public void testIsolateMasterAndVerifyClusterStateConsensus() throws Exception {
     /**
      * Test that we do not loose document whose indexing request was successful, under a randomly selected disruption scheme
      * We also collect & report the type of indexing failures that occur.
-     *
+     * <p/>
      * This test is a superset of tests run in the Jepsen test suite, with the exception of versioned updates
      */
     @Test
@@ -948,6 +952,50 @@ public void testNodeNotReachableFromMaster() throws Exception {
         ensureStableCluster(3);
     }
 
+    @Test
+    public void testIndexImportedFromDataOnlyNodesIfMasterLostDataFolder() throws Exception {
+        // test for https://github.com/elastic/elasticsearch/issues/8823
+        configureCluster(2, 1);
+        String masterNode = internalCluster().startMasterOnlyNode(Settings.EMPTY);
+        internalCluster().startDataOnlyNode(Settings.EMPTY);
+
+        ensureStableCluster(2);
+        assertAcked(prepareCreate("index").setSettings(Settings.builder().put("index.number_of_replicas", 0)));
+        index("index", "doc", "1", jsonBuilder().startObject().field("text", "some text").endObject());
+        ensureGreen();
+
+        internalCluster().restartNode(masterNode, new InternalTestCluster.RestartCallback() {
+            public boolean clearData(String nodeName) {
+                return true;
+            }
+        });
+
+        ensureGreen("index");
+        assertTrue(client().prepareGet("index", "doc", "1").get().isExists());
+    }
+
+    // tests if indices are really deleted even if a master transition inbetween
+    @Ignore("https://github.com/elastic/elasticsearch/issues/11665")
+    @Test
+    public void testIndicesDeleted() throws Exception {
+        configureCluster(3, 2);
+        Future<List<String>> masterNodes= internalCluster().startMasterOnlyNodesAsync(2);
+        Future<String> dataNode = internalCluster().startDataOnlyNodeAsync();
+        dataNode.get();
+        masterNodes.get();
+        ensureStableCluster(3);
+        assertAcked(prepareCreate("test"));
+        ensureYellow();
+
+        String masterNode1 = internalCluster().getMasterName();
+        NetworkPartition networkPartition = new NetworkUnresponsivePartition(masterNode1, dataNode.get(), getRandom());
+        internalCluster().setDisruptionScheme(networkPartition);
+        networkPartition.startDisrupting();
+        internalCluster().client(masterNode1).admin().indices().prepareDelete("test").setTimeout("1s").get();
+        internalCluster().restartNode(masterNode1, InternalTestCluster.EMPTY_CALLBACK);
+        ensureYellow();
+        assertFalse(client().admin().indices().prepareExists("test").get().isExists());
+    }
 
     protected NetworkPartition addRandomPartition() {
         NetworkPartition partition;