1 files changed, 42 insertions, 0 deletions
diff --git a/src/mongo/db/matcher/expression_algo_test.cpp b/src/mongo/db/matcher/expression_algo_test.cpp
index 8679c759cd5..3e0922bd9fc 100644
--- a/src/mongo/db/matcher/expression_algo_test.cpp
+++ b/src/mongo/db/matcher/expression_algo_test.cpp
@@ -181,6 +181,14 @@ TEST(ExpressionAlgoIsSubsetOf, CompareAnd_GT) {
     ASSERT_FALSE(expression::isSubsetOf(filter.get(), query.get()));
 }
 
+TEST(ExpressionAlgoIsSubsetOf, CompareAnd_SingleField) {
+    ParsedMatchExpression filter("{a: {$gt: 5, $lt: 7}}");
+    ParsedMatchExpression query("{a: {$gt: 5, $lt: 6}}");
+
+    ASSERT_TRUE(expression::isSubsetOf(query.get(), filter.get()));
+    ASSERT_FALSE(expression::isSubsetOf(filter.get(), query.get()));
+}
+
 TEST(ExpressionAlgoIsSubsetOf, CompareOr_LT) {
     ParsedMatchExpression lt5("{a: {$lt: 5}}");
     ParsedMatchExpression eq2OrEq3("{$or: [{a: 2}, {a: 3}]}");
@@ -931,6 +939,15 @@ TEST(IsIndependent, NonRenameableExpressionIsNotIndependent) {
     }
 }
 
+TEST(IsIndependent, EmptyDependencySetsPassIsOnlyDependentOn) {
+    BSONObj matchPredicate = fromjson("{}");
+    boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
+    auto swMatchExpression = MatchExpressionParser::parse(matchPredicate, std::move(expCtx));
+    ASSERT_OK(swMatchExpression.getStatus());
+    auto matchExpression = std::move(swMatchExpression.getValue());
+    ASSERT_TRUE(expression::isOnlyDependentOn(*matchExpression.get(), {}));
+}
+
 TEST(SplitMatchExpression, AndWithSplittableChildrenIsSplittable) {
     BSONObj matchPredicate = fromjson("{$and: [{a: 1}, {b: 1}]}");
     boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
@@ -1368,6 +1385,31 @@ TEST(SplitMatchExpression, ShouldMoveIndependentPredicateWhenThereAreMultipleRen
     ASSERT_FALSE(splitExpr.second.get());
 }
 
+TEST(SplitMatchExpression, ShouldNotSplitWhenRand) {
+    const auto randExpr = "{$expr: {$lt: [{$rand: {}}, {$const: 0.25}]}}";
+    const auto assertMatchDoesNotSplit = [&](const std::string& exprString) {
+        BSONObj matchPredicate = fromjson(exprString);
+        boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());
+        auto matcher = MatchExpressionParser::parse(matchPredicate, std::move(expCtx));
+        ASSERT_OK(matcher.getStatus());
+
+        auto&& [split, residual] =
+            expression::splitMatchExpressionBy(std::move(matcher.getValue()), {}, {});
+        ASSERT_FALSE(split.get());
+        ASSERT_TRUE(residual.get());
+
+        BSONObjBuilder oldBob;
+        residual->serialize(&oldBob, true);
+        ASSERT_BSONOBJ_EQ(oldBob.obj(), fromjson(randExpr));
+    };
+
+    // We should not push down a $match with a $rand expression.
+    assertMatchDoesNotSplit(randExpr);
+
+    // This is equivalent to 'randExpr'.
+    assertMatchDoesNotSplit("{$sampleRate: 0.25}");
+}
+
 TEST(ApplyRenamesToExpression, ShouldApplyBasicRenamesForAMatchWithExpr) {
     BSONObj matchPredicate = fromjson("{$expr: {$eq: ['$a.b', '$c']}}");
     boost::intrusive_ptr<ExpressionContextForTest> expCtx(new ExpressionContextForTest());