Comment/test for DocumentMarkerList::MarkersIntersectingRange() with collapsed range

third_party/WebKit/Source/core/editing/markers/DocumentMarkerListEditorTest.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/editing/markers/DocumentMarkerListEditor.h"
 
 #include "core/editing/markers/TextMatchMarker.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
@@ skipping 506 matching lines @@
   markers.push_back(CreateMarker(5, 10));
 
   DocumentMarkerListEditor::MarkerList markers_intersecting_range =
       DocumentMarkerListEditor::MarkersIntersectingRange(markers, 9, 15);
   EXPECT_EQ(1u, markers_intersecting_range.size());
 
   EXPECT_EQ(5u, markers_intersecting_range[0]->StartOffset());
   EXPECT_EQ(10u, markers_intersecting_range[0]->EndOffset());
 }
 
+TEST_F(DocumentMarkerListEditorTest, MarkersIntersectingRange_CollapsedRange) {
+  DocumentMarkerListEditor::MarkerList markers;
+  markers.push_back(CreateMarker(5, 10));
+
+  DocumentMarkerListEditor::MarkerList markers_intersecting_range =
+      DocumentMarkerListEditor::MarkersIntersectingRange(markers, 7, 7);
+  EXPECT_EQ(1u, markers_intersecting_range.size());
+
+  EXPECT_EQ(5u, markers_intersecting_range[0]->StartOffset());
+  EXPECT_EQ(10u, markers_intersecting_range[0]->EndOffset());
+}
+
 TEST_F(DocumentMarkerListEditorTest, MarkersIntersectingRange_MultipleMarkers) {
   DocumentMarkerListEditor::MarkerList markers;
   markers.push_back(CreateMarker(0, 5));
   markers.push_back(CreateMarker(5, 10));
   markers.push_back(CreateMarker(10, 15));
   markers.push_back(CreateMarker(15, 20));
   markers.push_back(CreateMarker(20, 25));
 
   DocumentMarkerListEditor::MarkerList markers_intersecting_range =
       DocumentMarkerListEditor::MarkersIntersectingRange(markers, 7, 17);
   EXPECT_EQ(3u, markers_intersecting_range.size());
 
   EXPECT_EQ(5u, markers_intersecting_range[0]->StartOffset());
   EXPECT_EQ(10u, markers_intersecting_range[0]->EndOffset());
 
   EXPECT_EQ(10u, markers_intersecting_range[1]->StartOffset());
   EXPECT_EQ(15u, markers_intersecting_range[1]->EndOffset());
 
   EXPECT_EQ(15u, markers_intersecting_range[2]->StartOffset());
   EXPECT_EQ(20u, markers_intersecting_range[2]->EndOffset());
 }
 
 }  // namespace blink