1 files changed, 53 insertions, 0 deletions
diff --git a/jstests/aggregation/unwind.js b/jstests/aggregation/unwind.js
index ffd2a3da9c6..cf01560cc0c 100644
--- a/jstests/aggregation/unwind.js
+++ b/jstests/aggregation/unwind.js
@@ -15,3 +15,56 @@ assert.eq(4, res.length);
 assert.eq([1, 2, 3, 4], res.map(function(z) {
     return z.x;
 }));
+
+// Test unwinding an empty path
+coll = db.agg_unwind_empty_path;
+coll.drop();
+coll.insert({_id: 1});
+coll.insert({_id: 2, "": [1, 2]});
+coll.insert({_id: 3, "": {"": [3, 4, 5]}});
+
+assert.throwsWithCode(() => coll.aggregate([{$unwind: {path: "$"}}]).toArray(), 40352);
+assert.throwsWithCode(() => coll.aggregate([{$unwind: {path: "$."}}]).toArray(), 40353);
+
+// Test includeArrayIndex
+coll = db.agg_unwind_with_index;
+coll.drop();
+coll.insert({_id: 1});
+coll.insert({_id: 2, array: [1, 2]});
+coll.insert({_id: 3, obj: {array: [3, 4, 5]}});
+coll.insert({_id: 4, obj: {subObj: {array: [6, 7, 8, 9]}}});
+
+assert.eq(
+    coll.aggregate([{$unwind: {path: "$array", includeArrayIndex: "idx"}}]).toArray(),
+    [{"_id": 2, "array": 1, "idx": NumberLong(0)}, {"_id": 2, "array": 2, "idx": NumberLong(1)}]);
+
+assert.eq(coll.aggregate([{$unwind: {path: "$array", includeArrayIndex: "array"}}]).toArray(),
+          [{"_id": 2, "array": NumberLong(0)}, {"_id": 2, "array": NumberLong(1)}]);
+
+assert.eq(coll.aggregate([{$unwind: {path: "$obj.array", includeArrayIndex: "idx"}}]).toArray(), [
+    {"_id": 3, "obj": {"array": 3}, "idx": NumberLong(0)},
+    {"_id": 3, "obj": {"array": 4}, "idx": NumberLong(1)},
+    {"_id": 3, "obj": {"array": 5}, "idx": NumberLong(2)}
+]);
+
+assert.eq(coll.aggregate([{$unwind: {path: "$obj.array", includeArrayIndex: "obj"}}]).toArray(), [
+    {"_id": 3, "obj": NumberLong(0)},
+    {"_id": 3, "obj": NumberLong(1)},
+    {"_id": 3, "obj": NumberLong(2)}
+]);
+
+assert.eq(
+    coll.aggregate([{$unwind: {path: "$obj.array", includeArrayIndex: "obj.array"}}]).toArray(), [
+        {"_id": 3, "obj": {"array": NumberLong(0)}},
+        {"_id": 3, "obj": {"array": NumberLong(1)}},
+        {"_id": 3, "obj": {"array": NumberLong(2)}}
+    ]);
+
+assert.eq(coll.aggregate([{$unwind: {path: "$obj.subObj.array", includeArrayIndex: "obj.subObj"}}])
+              .toArray(),
+          [
+              {"_id": 4, "obj": {"subObj": NumberLong(0)}},
+              {"_id": 4, "obj": {"subObj": NumberLong(1)}},
+              {"_id": 4, "obj": {"subObj": NumberLong(2)}},
+              {"_id": 4, "obj": {"subObj": NumberLong(3)}}
+          ]);