1 files changed, 21 insertions, 0 deletions
diff --git a/src/mongo/db/matcher/expression_optimize_test.cpp b/src/mongo/db/matcher/expression_optimize_test.cpp
index eaa606e06df..04d2bc29e11 100644
--- a/src/mongo/db/matcher/expression_optimize_test.cpp
+++ b/src/mongo/db/matcher/expression_optimize_test.cpp
@@ -495,5 +495,26 @@ TEST(ExpressionOptimizeTest, OrRewrittenToIn) {
     ASSERT_BSONOBJ_EQ(optimizeExpr(queries[10].first), fromjson(queries[10].second));
 }
 
+TEST(ExpressionOptimizeTest, NorRemovesAlwaysFalseChildren) {
+    BSONObj obj = fromjson("{$nor: [{a: 1}, {$alwaysFalse: 1}]}");
+    std::unique_ptr<MatchExpression> matchExpression(parseMatchExpression(obj));
+    auto optimizedMatchExpression = MatchExpression::optimize(std::move(matchExpression));
+    ASSERT_BSONOBJ_EQ(optimizedMatchExpression->serialize(), fromjson("{a: {$not: {$eq: 1}}}"));
+}
+
+TEST(ExpressionOptimizeTest, NorWithoutChildrenOptimizesToEmptyAnd) {
+    BSONObj obj = fromjson("{$nor: [{$alwaysFalse: 1}, {$alwaysFalse: 1}]}");
+    std::unique_ptr<MatchExpression> matchExpression(parseMatchExpression(obj));
+    auto optimizedMatchExpression = MatchExpression::optimize(std::move(matchExpression));
+    ASSERT_TRUE(dynamic_cast<AndMatchExpression*>(optimizedMatchExpression.get()));
+    ASSERT_BSONOBJ_EQ(optimizedMatchExpression->serialize(), fromjson("{}"));
+}
+
+TEST(ExpressionOptimizeTest, NorWithAlwaysTrueChildOptimizesToAlwaysFalse) {
+    BSONObj obj = fromjson("{$nor: [{a: 1}, {$alwaysTrue: 1}]}");
+    std::unique_ptr<MatchExpression> matchExpression(parseMatchExpression(obj));
+    auto optimizedMatchExpression = MatchExpression::optimize(std::move(matchExpression));
+    ASSERT_BSONOBJ_EQ(optimizedMatchExpression->serialize(), fromjson("{$alwaysFalse: 1}"));
+}
 }  // namespace
 }  // namespace mongo