From edd902cd18bfc43ffec2aea04c7cc6c870c3211a Mon Sep 17 00:00:00 2001
From: Josip Mrden <josip.mrden@memgraph.io>
Date: Fri, 23 Jun 2023 14:47:41 +0200
Subject: [PATCH] Fix cost estimator test

---
 src/query/plan/cost_estimator.hpp   | 8 ++------
 tests/unit/query_cost_estimator.cpp | 2 +-
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/query/plan/cost_estimator.hpp b/src/query/plan/cost_estimator.hpp
index 04af448a9..ab1a928e8 100644
--- a/src/query/plan/cost_estimator.hpp
+++ b/src/query/plan/cost_estimator.hpp
@@ -302,13 +302,9 @@ class CostEstimator : public HierarchicalLogicalOperatorVisitor {
     // Estimate cost on the subquery branch independently, use a copy
     auto last_scope = scopes_.back();
     double subquery_cost = EstimateCostOnBranch(&op.subquery_, last_scope);
+    subquery_cost = subquery_cost != 0 ? subquery_cost : 1;
+    cardinality_ *= subquery_cost;
 
-    // if the query is a unit subquery, we don't want the cost to be zero but 1xN
-    double input_cost = cost();
-    input_cost = input_cost == 0 ? 1 : input_cost;
-    subquery_cost = subquery_cost == 0 ? 1 : subquery_cost;
-
-    cardinality_ *= input_cost * subquery_cost;
     IncrementCost(CostParam::kSubquery);
 
     return false;
diff --git a/tests/unit/query_cost_estimator.cpp b/tests/unit/query_cost_estimator.cpp
index bd1fee60b..d89031b82 100644
--- a/tests/unit/query_cost_estimator.cpp
+++ b/tests/unit/query_cost_estimator.cpp
@@ -201,7 +201,7 @@ TEST_F(QueryCostEstimator, SubqueryCartesian) {
   std::shared_ptr<LogicalOperator> input = std::make_shared<ScanAll>(std::make_shared<Once>(), NextSymbol());
   std::shared_ptr<LogicalOperator> subquery = std::make_shared<ScanAll>(std::make_shared<Once>(), NextSymbol());
   MakeOp<memgraph::query::plan::Apply>(input, subquery, true);
-  EXPECT_COST(CostParam::kSubquery * no_vertices * no_vertices);
+  EXPECT_COST(CostParam::kSubquery * no_vertices * no_vertices + no_vertices);
 }
 
 TEST_F(QueryCostEstimator, UnitSubquery) {