diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7dedc63..7d97db8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,12 +4,14 @@ project(TDD)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+enable_testing()
 
 add_subdirectory(src/calculator)
 add_subdirectory(src/bj1094)
 
 
 # GoogleTest
+
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 add_subdirectory(gtest)
 add_subdirectory(test/calculator)
@@ -23,5 +25,4 @@ if(COVERAGE)
     add_link_options(--coverage)
 endif()
 
-enable_testing()
 include(GoogleTest)
diff --git a/include/queue/queue.hpp b/include/queue/queue.hpp
index 05f2dfe..d5147b6 100644
--- a/include/queue/queue.hpp
+++ b/include/queue/queue.hpp
@@ -18,6 +18,8 @@ class Queue {
     Data pull();
     Data top();
     int size();
+    bool is_full();
+    bool is_empty();
 };
 
 #include "queue.tpp"
diff --git a/include/queue/queue.tpp b/include/queue/queue.tpp
index b7f341c..f2da377 100644
--- a/include/queue/queue.tpp
+++ b/include/queue/queue.tpp
@@ -18,19 +18,45 @@ void Queue<Data>::clear() {
 
 template<class Data>
 void Queue<Data>::push(Data data) {
+    if (is_full()) {
+        throw std::runtime_error("Queue is full");
+    }
+    
+    buffer[ep] = data;
+    ep = (ep + 1) % QUEUE_SIZE;
 }
 
 template<class Data>
 Data Queue<Data>::pull() {
-    return buffer[sp];
+    if (is_empty()) {
+        throw std::runtime_error("Queue is empty");
+    }
+
+    Data result = buffer[sp];
+    sp = (sp + 1) % QUEUE_SIZE;
+    return result;
 }
 
 template<class Data>
 Data Queue<Data>::top() {
+    if (is_empty()) {
+        throw std::runtime_error("Queue is empty");
+    }
+
     return buffer[sp];
 }
 
 template<class Data>
 int Queue<Data>::size() {
-    return 0;
+    return (ep - sp + QUEUE_SIZE) % QUEUE_SIZE;
+}
+
+template<class Data>
+bool Queue<Data>::is_full() {
+    return ep == (sp - 1 + QUEUE_SIZE) % QUEUE_SIZE;
+}
+
+template<class Data>
+bool Queue<Data>::is_empty() {
+    return sp == ep;
 }
\ No newline at end of file
diff --git a/test/queue/queue_test.cpp b/test/queue/queue_test.cpp
index 53b76a1..dcbfeee 100644
--- a/test/queue/queue_test.cpp
+++ b/test/queue/queue_test.cpp
@@ -7,7 +7,6 @@ using namespace std;
 class QueueTest : public ::testing::Test {
 protected:
     Queue<int> int_queue;
-    Queue<string> string_queue;
 
     void SetUp() override {
         int_queue.clear();
@@ -42,4 +41,49 @@ TEST_F(QueueTest, push_and_pull) {
 
     // then
     EXPECT_EQ(second, v2);
-}
\ No newline at end of file
+}
+
+TEST_F(QueueTest, size) {    
+    // given
+    int_queue.push(1);
+    int_queue.push(2);
+    int_queue.push(3);
+
+    // when
+    int size = int_queue.size();
+
+    // then
+    EXPECT_EQ(size, 3);
+}
+
+TEST_F(QueueTest, clear) {    
+    // given
+    int_queue.push(1);
+    int_queue.push(2);
+    int_queue.push(3);
+
+    // when
+    int_queue.clear();
+    int size = int_queue.size();
+
+    // then
+    EXPECT_EQ(size, 0);
+}
+
+TEST_F(QueueTest, empty_pull) {    
+    EXPECT_THROW(int_queue.pull(), std::runtime_error);
+}
+
+TEST_F(QueueTest, empty_top) {    
+    EXPECT_THROW(int_queue.top(), std::runtime_error);
+}
+
+TEST_F(QueueTest, full_push) {    
+    // given
+    for (int i = 0; i < QUEUE_SIZE - 1; i++) {
+        int_queue.push(i);
+    }
+
+    // then
+    EXPECT_THROW(int_queue.push(QUEUE_SIZE), std::runtime_error);
+}   
\ No newline at end of file
diff --git a/test/queue/string_queue_test.cpp b/test/queue/string_queue_test.cpp
new file mode 100644
index 0000000..2367351
--- /dev/null
+++ b/test/queue/string_queue_test.cpp
@@ -0,0 +1,71 @@
+#include <gtest/gtest.h>
+#include <string>
+#include "queue/queue.hpp"
+
+using namespace std;
+
+class StringQueueTest : public ::testing::Test {
+protected:
+    Queue<string> string_queue;
+
+    void SetUp() override {
+        string_queue.clear();
+    }
+
+    void TearDown() override {
+    }
+};
+
+TEST_F(StringQueueTest, push_and_top) {    
+    // given
+    string value = "hello";
+    string_queue.push(value);
+
+    // when
+    string top = string_queue.top();
+
+    // then
+    EXPECT_EQ(top, value);
+}
+
+TEST_F(StringQueueTest, push_and_pull) {    
+    // given
+    string v1 = "hello";
+    string v2 = "world";
+    string_queue.push(v1);
+    string_queue.push(v2);
+
+    // when
+    string_queue.pull();
+    string second = string_queue.pull();
+
+    // then
+    EXPECT_EQ(second, v2);
+}
+
+TEST_F(StringQueueTest, size) {    
+    // given
+    string_queue.push("hello");
+    string_queue.push("world");
+    string_queue.push("!");
+
+    // when
+    int size = string_queue.size();
+
+    // then
+    EXPECT_EQ(size, 3);
+}
+
+TEST_F(StringQueueTest, clear) {    
+    // given
+    string_queue.push("hello");
+    string_queue.push("world");
+    string_queue.push("!");
+
+    // when
+    string_queue.clear();
+    int size = string_queue.size();
+
+    // then
+    EXPECT_EQ(size, 0);
+}
\ No newline at end of file