1 files changed, 35 insertions, 0 deletions
diff --git a/jstests/core/find_dedup.js b/jstests/core/find_dedup.js
new file mode 100644
index 00000000000..401384ceb7a
--- /dev/null
+++ b/jstests/core/find_dedup.js
@@ -0,0 +1,35 @@
+// Test that duplicate query results are not returned.
+
+var t = db.jstests_find_dedup;
+
+function checkDedup(query, idArray) {
+    resultsArr = t.find(query).toArray();
+    assert.eq(resultsArr.length, idArray.length, "same number of results");
+
+    for (var i = 0; i < idArray.length; i++) {
+        assert(("_id" in resultsArr[i]), "result doc missing _id");
+        assert.eq(idArray[i], resultsArr[i]._id, "_id mismatch for doc " + i);
+    }
+}
+
+// Deduping $or
+t.drop();
+t.ensureIndex({a: 1, b: 1});
+t.save({_id: 1, a: 1, b: 1});
+t.save({_id: 2, a: 1, b: 1});
+t.save({_id: 3, a: 2, b: 2});
+t.save({_id: 4, a: 3, b: 3});
+t.save({_id: 5, a: 3, b: 3});
+checkDedup({$or: [{a:{$gte:0,$lte:2},b:{$gte:0,$lte:2}},
+                  {a:{$gte:1,$lte:3},b:{$gte:1,$lte:3}},
+                  {a:{$gte:1,$lte:4},b:{$gte:1,$lte:4}}]},
+           [1, 2, 3, 4, 5]);
+
+// Deduping multikey
+t.drop();
+t.save({_id: 1, a: [1, 2, 3], b: [4, 5, 6]});
+t.save({_id: 2, a: [1, 2, 3], b: [4, 5, 6]});
+assert.eq( 2, t.count() );
+checkDedup({$or: [{a: {$in: [1, 2]}}, {b: {$in: [4, 5]}}]}, [1, 2]);
+t.ensureIndex( { a : 1 } );
+checkDedup({$or: [{a: {$in: [1, 2]}}, {b: {$in: [4, 5]}}]}, [1, 2]);