Fix off by one error in test

./gradlew ':x-pack:plugin:searchable-snapshots:qa:rest:integTestRunner' \
 --tests "org.elasticsearch.xpack.searchablesnapshots.rest.FsSearchableSnapshotsIT.testSearchResults" \
  -Dtests.seed=5B626133268C101A \
  -Dtests.security.manager=true \
  -Dtests.locale=ro-RO \
  -Dtests.timezone=America/Port-au-Prince \
  -Dcompiler.java=13

Author: tlrx

x-pack/plugin/searchable-snapshots/src/test/java/org/elasticsearch/xpack/searchablesnapshots/AbstractSearchableSnapshotsRestTestCase.java

@@ -206,12 +206,11 @@ public void testClearCache() throws Exception {
     }
 
     public void assertSearchResults(String indexName, int numDocs, Boolean ignoreThrottled) throws IOException {
-        final int randomTieBreaker = randomIntBetween(1, numDocs - 1);
+        final int randomTieBreaker = randomIntBetween(0, numDocs - 1);
         Map<String, Object> searchResults;
         switch (randomInt(3)) {
             case 0:
-                searchResults
-                    = search(indexName, QueryBuilders.termQuery("field", String.valueOf(randomTieBreaker)), ignoreThrottled);
+                searchResults = search(indexName, QueryBuilders.termQuery("field", String.valueOf(randomTieBreaker)), ignoreThrottled);
                 assertThat(extractValue(searchResults, "hits.total.value"), equalTo(1));
                 @SuppressWarnings("unchecked")
                 Map<String, Object> searchHit = (Map<String, Object>) ((List<?>) extractValue(searchResults, "hits.hits")).get(0);