diff --git a/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.cpp b/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.cpp
index bcf753d..7bebb39 100644
--- a/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.cpp
+++ b/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.cpp
@@ -2,12 +2,16 @@
 
 namespace assignments::one::final_grade_determinator {
 
-FinalGradeDeterminator::FinalGradeDeterminator() : Node("final_grade_determinator") {
+FinalGradeDeterminator::FinalGradeDeterminator(std::unique_ptr<DatabaseManager> db_manager) : Node("final_grade_determinator") {
     this->declare_parameter("grade_collection_amount", 5);
     grade_collection_amount_ = this->get_parameter("grade_collection_amount").as_int();
 
-    db_manager_ = std::make_unique<DatabaseManager>(this->get_logger());
-
+    // Make db_manager optional for testing purposes
+    if (db_manager) {
+        db_manager_ = std::move(db_manager);
+    } else {
+        db_manager_ = std::make_unique<DatabaseManager>(this->get_logger());
+    }
     // Create publisher for exam results
     student_publisher_ = this->create_publisher<g2_2025_interfaces::msg::Student>(
         "student_course_management", 10
diff --git a/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.hpp b/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.hpp
index 8703bc7..b9db482 100644
--- a/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.hpp
+++ b/src/g2_2025_grade_calculator_pkg/src/final_grade_determinator/nodes/FinalGradeDeterminator.hpp
@@ -18,7 +18,7 @@ namespace assignments::one::final_grade_determinator {
 
 class FinalGradeDeterminator : public rclcpp::Node {
 public:
-    FinalGradeDeterminator();
+    FinalGradeDeterminator(std::unique_ptr<DatabaseManager> db_manager = nullptr);
 private:
     rclcpp::Subscription<g2_2025_interfaces::msg::Exam>::SharedPtr exam_subscriber_;
     rclcpp::Publisher<g2_2025_interfaces::msg::Student>::SharedPtr student_publisher_;