Treat document V1 API visiting timeouts with progress as successful (#2401)

Previously, using a visitor with a selection that did not match any buckets
visited during the session's lifetime would trigger a timeout error to the
client and abort the visiting. With this change, we special case timeouts if
they have successfully visited at least 1 bucket and return a successful
response for these. The client can then use the updated continuation token
for its subsequent request and continue from where the timed out session
left off.

The timeout special cased handling is done _outside_ the session and control
handler to avoid increasing session-internal complexity, and since not all
visitor use cases want this behavior (e.g. streaming search).

1 files changed, 39 insertions, 0 deletions

diff --git a/documentapi/src/test/java/com/yahoo/documentapi/messagebus/test/VisitorControlHandlerTest.java b/documentapi/src/test/java/com/yahoo/documentapi/messagebus/test/VisitorControlHandlerTest.java
new file mode 100644
index 00000000000..d8340e6a3f6
--- /dev/null
+++ b/documentapi/src/test/java/com/yahoo/documentapi/messagebus/test/VisitorControlHandlerTest.java
@@ -0,0 +1,39 @@
+// Copyright 2017 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.documentapi.messagebus.test;
+
+import com.yahoo.documentapi.VisitorControlHandler;
+import com.yahoo.vdslib.VisitorStatistics;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class VisitorControlHandlerTest {
+
+    @Test
+    public void has_visited_any_buckets_is_false_if_no_bucket_stats_recorded() {
+        VisitorControlHandler handler = new VisitorControlHandler();
+        assertFalse(handler.hasVisitedAnyBuckets());
+    }
+
+    @Test
+    public void has_visited_any_buckets_is_false_if_zero_buckets_visited() {
+        VisitorControlHandler handler = new VisitorControlHandler();
+        VisitorStatistics stats = new VisitorStatistics();
+        stats.setBucketsVisited(0);
+        handler.onVisitorStatistics(stats);
+
+        assertFalse(handler.hasVisitedAnyBuckets());
+    }
+
+    @Test
+    public void has_visited_any_buckets_is_true_if_more_than_zero_buckets_visited() {
+        VisitorControlHandler handler = new VisitorControlHandler();
+        VisitorStatistics stats = new VisitorStatistics();
+        stats.setBucketsVisited(1);
+        handler.onVisitorStatistics(stats);
+
+        assertTrue(handler.hasVisitedAnyBuckets());
+    }
+
+}