[CBO] Join Order test improvement (#8602)

Author: pashandor789

ydb/core/kqp/ut/join/kqp_join_order_ut.cpp

@@ -374,40 +374,15 @@ Y_UNIT_TEST_SUITE(KqpJoinOrder) {
 
     Y_UNIT_TEST_XOR_OR_BOTH_FALSE(TestJoinOrderHintsComplex, StreamLookupJoin, ColumnStore) {
         auto plan = ExecuteJoinOrderTestDataQueryWithStats("queries/join_order_hints_complex.sql", "stats/basic.json", StreamLookupJoin, ColumnStore); 
-        UNIT_ASSERT_VALUES_EQUAL(GetJoinOrder(plan).GetStringRobust(), R"([[["R","S"],["T","U"]],"V"])") ;
-    }
-
-    void TraverseJoinTree(
-        const NJson::TJsonValue& tree, 
-        std::function<void(const NJson::TJsonValue&, const NJson::TJsonValue&)> joinVisitFunc
-    ) {
-        if (tree.IsArray()) {
-            auto join = tree.GetArray();
-            Y_ENSURE(join.size() == 2, Sprintf("Incorrect join tree piece, expected 2 children for join, got : %s", tree.GetStringRobust().c_str()));
-            joinVisitFunc(join[0], join[1]);
-            TraverseJoinTree(join[0], joinVisitFunc);
-            TraverseJoinTree(join[1], joinVisitFunc);
-        } else if (tree.IsString()) {
-        } else {
-            Y_ENSURE(false, Sprintf("Incorrect join tree piece: %s", tree.GetStringRobust().c_str()));
-        }
+        auto joinOrder = GetJoinOrder(plan).GetStringRobust();
+        UNIT_ASSERT_C(joinOrder.find(R"([["R","S"],["T","U"]])") != TString::npos, joinOrder);
     }
 
     Y_UNIT_TEST_XOR_OR_BOTH_FALSE(TestJoinOrderHintsManyHintTrees, StreamLookupJoin, ColumnStore) {
         auto plan = ExecuteJoinOrderTestDataQueryWithStats("queries/join_order_hints_many_hint_trees.sql", "stats/basic.json", StreamLookupJoin, ColumnStore); 
-        auto joinOrder = GetJoinOrder(plan);
-
-        THashSet<TString> expectedJoins = { "R, S", "T, U" };
-        TraverseJoinTree(
-            joinOrder, 
-            [&expectedJoins](const NJson::TJsonValue& joinLhs, const NJson::TJsonValue& joinRhs){ 
-                if (joinLhs.IsString() && joinRhs.IsString()) {
-                    expectedJoins.erase(Sprintf("%s, %s", joinLhs.GetString().c_str(), joinRhs.GetString().c_str()));
-                }
-            }
-        );
-
-        UNIT_ASSERT_C(expectedJoins.empty(), Sprintf("%s wasn't found in '%s' join order!", JoinSeq(", ", expectedJoins).c_str(), joinOrder.GetStringRobust().c_str()));
+        auto joinOrder = GetJoinOrder(plan).GetStringRobust();
+        UNIT_ASSERT_C(joinOrder.find(R"(["R","S"])") != TString::npos, joinOrder);
+        UNIT_ASSERT_C(joinOrder.find(R"(["T","U"])") != TString::npos, joinOrder);
     }
 
     void JoinOrderTestWithOverridenStats(const TString& queryPath, const TString& statsPath, TString correctJoinOrderPath, bool useStreamLookupJoin, bool useColumnStore