From 13a8ba4740f1bda86fd06fa6a56afe07f3c3bd3a Mon Sep 17 00:00:00 2001
From: Simon Willnauer <simonw@apache.org>
Date: Tue, 20 Feb 2018 09:34:20 +0100
Subject: [PATCH] [TEST] Fix flaky IndexServiceTests#testRefreshActuallyWorks

---
 .../index/IndexServiceTests.java              | 47 ++++++++++++++-----
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/server/src/test/java/org/elasticsearch/index/IndexServiceTests.java b/server/src/test/java/org/elasticsearch/index/IndexServiceTests.java
index df6aa962f31..bd2170dc1ee 100644
--- a/server/src/test/java/org/elasticsearch/index/IndexServiceTests.java
+++ b/server/src/test/java/org/elasticsearch/index/IndexServiceTests.java
@@ -194,25 +194,46 @@ public class IndexServiceTests extends ESSingleNodeTestCase {
         IndexService.AsyncRefreshTask refreshTask = indexService.getRefreshTask();
         assertEquals(1000, refreshTask.getInterval().millis());
         assertTrue(indexService.getRefreshTask().mustReschedule());
-
-        // now disable
-        IndexMetaData metaData = IndexMetaData.builder(indexService.getMetaData()).settings(Settings.builder().put(indexService.getMetaData().getSettings()).put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), -1)).build();
-        indexService.updateMetaData(metaData);
-        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
         IndexShard shard = indexService.getShard(0);
-        try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
-            TopDocs search = searcher.searcher().search(new MatchAllDocsQuery(), 10);
-            assertEquals(0, search.totalHits);
-        }
-        // refresh every millisecond
-        metaData = IndexMetaData.builder(indexService.getMetaData()).settings(Settings.builder().put(indexService.getMetaData().getSettings()).put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "1ms")).build();
+        client().prepareIndex("test", "test", "0").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        // now disable the refresh
+        IndexMetaData metaData = IndexMetaData.builder(indexService.getMetaData())
+            .settings(Settings.builder().put(indexService.getMetaData().getSettings())
+                .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), -1)).build();
+        // when we update we reschedule the existing task AND fire off an async refresh to make sure we make everything visible
+        // before that this is why we need to wait for the refresh task to be unscheduled and the first doc to be visible
         indexService.updateMetaData(metaData);
+        assertTrue(refreshTask.isClosed());
+        refreshTask = indexService.getRefreshTask();
         assertBusy(() -> {
+            // this one either becomes visible due to a concurrently running scheduled refresh OR due to the force refresh
+            // we are running on updateMetaData if the interval changes
             try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
                 TopDocs search = searcher.searcher().search(new MatchAllDocsQuery(), 10);
                 assertEquals(1, search.totalHits);
-            } catch (IOException e) {
-                fail(e.getMessage());
+            }
+        });
+        assertFalse(refreshTask.isClosed());
+        // refresh every millisecond
+        client().prepareIndex("test", "test", "1").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        metaData = IndexMetaData.builder(indexService.getMetaData())
+            .settings(Settings.builder().put(indexService.getMetaData().getSettings())
+                .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), "1ms")).build();
+        indexService.updateMetaData(metaData);
+        assertTrue(refreshTask.isClosed());
+        assertBusy(() -> {
+            // this one becomes visible due to the force refresh we are running on updateMetaData if the interval changes
+            try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
+                TopDocs search = searcher.searcher().search(new MatchAllDocsQuery(), 10);
+                assertEquals(2, search.totalHits);
+            }
+        });
+        client().prepareIndex("test", "test", "2").setSource("{\"foo\": \"bar\"}", XContentType.JSON).get();
+        assertBusy(() -> {
+            // this one becomes visible due to the scheduled refresh
+            try (Engine.Searcher searcher = shard.acquireSearcher("test")) {
+                TopDocs search = searcher.searcher().search(new MatchAllDocsQuery(), 10);
+                assertEquals(3, search.totalHits);
             }
         });
     }