diff --git a/bin/ftsort/ftsort.cpp b/bin/ftsort/ftsort.cpp
index 5143542..2f473a1 100644
--- a/bin/ftsort/ftsort.cpp
+++ b/bin/ftsort/ftsort.cpp
@@ -1,19 +1,27 @@
 #include "tape_config.h"
+#include "tapelib/filetape.h"
+#include "tapelib/tape.h"
 #include "tapelib/tape_util.h"
 #include <chrono>
 #include <cstddef>
 #include <fstream>
 #include <iostream>
+#include <memory>
 #include <string>
 
+using std::string;
+using std::chrono::high_resolution_clock;
+using std::chrono::milliseconds;
+using namespace tape;
+
 size_t get_mem_peak() {
-    const static std::string mem_info_file = "/proc/self/status";
-    const static std::string mem_field = "VmPeak:";
+    const static string mem_info_file = "/proc/self/status";
+    const static string mem_field = "VmPeak:";
     std::ifstream status(mem_info_file);
     size_t mem = 0;
-    std::string line;
+    string line;
     while (std::getline(status, line)) {
-        if (line.find(mem_field) != std::string::npos) {
+        if (line.find(mem_field) != string::npos) {
             std::stringstream mem_line(line.substr(mem_field.size()));
             mem_line >> mem;
             return mem;
@@ -36,29 +44,27 @@ int main(int argc, char *argv[]) {
         !read_settings_from_file(settings)) {
         return -1;
     }
-    tape::FileTape input(settings.input_file_name, settings.ft_settings);
+    FileTape input(settings.input_file_name, settings.ft_settings);
     if (!input.is_open()) {
         std::cerr << "Failed to create INPUT tape - file not found or "
                      "insufficient permissions"
                   << std::endl;
         return -1;
     }
-    tape::FileTape output(input, settings.output_file_name,
-                          settings.ft_settings);
+    FileTape output(input, settings.output_file_name, settings.ft_settings);
     if (!output.is_open()) {
         std::cerr << "Failed to create OUTPUT tape - insufficient permissions"
                   << std::endl;
         return -1;
     }
     // tmp tape factory that captures settings.ft_settings from local scope
-    tape::TempTapeFactory factory =
-        [&](size_t cells) -> std::unique_ptr<tape::Tape> {
-        return std::make_unique<tape::FileTape>(
-            tape::FileTape(cells, settings.ft_settings));
+    TempTapeFactory factory = [&](size_t cells) -> std::unique_ptr<Tape> {
+        return std::make_unique<FileTape>(
+            FileTape(cells, settings.ft_settings));
     };
-    auto start = std::chrono::high_resolution_clock::now();
-    tape::external_sort(input, output, factory, settings.memory_limit);
-    auto end = std::chrono::high_resolution_clock::now();
+    auto start = high_resolution_clock::now();
+    external_sort(input, output, factory, settings.memory_limit);
+    auto end = high_resolution_clock::now();
     auto duration = std::chrono::duration_cast<milliseconds>(end - start);
     std::cout << "Successfully sorted " << settings.input_file_name << " into "
               << settings.output_file_name << std::endl;
diff --git a/bin/ftsort/tape_config.cpp b/bin/ftsort/tape_config.cpp
index c3659fa..9e048b7 100644
--- a/bin/ftsort/tape_config.cpp
+++ b/bin/ftsort/tape_config.cpp
@@ -1,10 +1,17 @@
 #include "tape_config.h"
+#include "tapelib/filetape.h"
 #include <bits/getopt_core.h>
+#include <chrono>
+#include <cstddef>
 #include <fstream>
 #include <getopt.h>
 #include <iostream>
 #include <stdexcept>
 #include <string>
+#include <vector>
+
+using std::string;
+using std::chrono::milliseconds;
 
 const static struct std::vector<option> CMD_OPTS{
     {.name = "write-delay",
@@ -32,9 +39,9 @@ const static struct std::vector<option> CMD_OPTS{
     {.name = "help", .has_arg = no_argument, .flag = nullptr, .val = 'h'},
     {.name = nullptr, .has_arg = no_argument, .flag = nullptr, .val = 0}};
 
-std::chrono::milliseconds parse_delay(const std::string &input) {
+milliseconds parse_delay(const string &input) {
     int delay_ms = std::stoi(input);
-    return std::chrono::milliseconds(delay_ms);
+    return milliseconds(delay_ms);
 }
 
 AppSettings parse_command_line(int argc, char **argv) {
@@ -105,15 +112,15 @@ bool read_settings_from_file(AppSettings &settings) {
                   << std::endl;
         return false;
     }
-    std::string line;
+    string line;
     size_t line_number = 1;
     while (std::getline(config, line)) {
         size_t delim_index = line.find(CFG_DELIMETER);
         if (delim_index >= line.size()) {
             continue;
         }
-        std::string key = line.substr(0, delim_index);
-        std::string value = line.substr(delim_index + 1);
+        string key = line.substr(0, delim_index);
+        string value = line.substr(delim_index + 1);
         try {
             if (key == "write-delay") {
                 settings.ft_settings.write_delay = parse_delay(value);
diff --git a/bin/ftsort/tape_config.h b/bin/ftsort/tape_config.h
index 070bb09..b571c6f 100644
--- a/bin/ftsort/tape_config.h
+++ b/bin/ftsort/tape_config.h
@@ -2,6 +2,8 @@
 #define TAPE_CONFIG_H
 
 #include "tapelib/filetape.h"
+#include <cstddef>
+#include <string>
 
 // stringizing opearator to convert macro into string literal
 #define xstr(s) str(s)
diff --git a/include/tapelib/filetape.h b/include/tapelib/filetape.h
index 6aea7c8..a9a577f 100644
--- a/include/tapelib/filetape.h
+++ b/include/tapelib/filetape.h
@@ -3,11 +3,12 @@
 
 #include "tape.h"
 #include <chrono>
+#include <cstddef>
+#include <cstdint>
 #include <fstream>
+#include <string>
 #include <vector>
 
-using std::chrono::milliseconds;
-
 namespace tape {
 
 /**
@@ -15,17 +16,17 @@ namespace tape {
  * such as read dealy, write delay etc.
  */
 struct FileTapeSettings {
-    milliseconds read_delay;
-    milliseconds write_delay;
-    milliseconds seek_forward_delay;
-    milliseconds seek_backwards_delay;
+    std::chrono::milliseconds read_delay;
+    std::chrono::milliseconds write_delay;
+    std::chrono::milliseconds seek_forward_delay;
+    std::chrono::milliseconds seek_backwards_delay;
 };
 
 const static struct FileTapeSettings FT_DEFAULT_SETTINGS =
-    FileTapeSettings{.read_delay = milliseconds(0),
-                     .write_delay = milliseconds(0),
-                     .seek_forward_delay = milliseconds(0),
-                     .seek_backwards_delay = milliseconds(0)};
+    FileTapeSettings{.read_delay = std::chrono::milliseconds(0),
+                     .write_delay = std::chrono::milliseconds(0),
+                     .seek_forward_delay = std::chrono::milliseconds(0),
+                     .seek_backwards_delay = std::chrono::milliseconds(0)};
 
 const static char FT_DELIMETER = '\n';
 
diff --git a/include/tapelib/tape_util.h b/include/tapelib/tape_util.h
index 835b1cd..f237b99 100644
--- a/include/tapelib/tape_util.h
+++ b/include/tapelib/tape_util.h
@@ -8,21 +8,19 @@
 #include <functional>
 #include <memory>
 
-using std::unique_ptr;
-
 namespace tape {
 
 /**
  * Lambda, which takes the amount of cells a tape should have and returns
  * a unique pointer to a temporary Tape with the specified amount of cells
  */
-using TempTapeFactory = std::function<unique_ptr<Tape>(size_t)>;
+using TempTapeFactory = std::function<std::unique_ptr<Tape>(size_t)>;
 
 /**
  * TempTapeFactory that creates a new temporary FileTape
  */
 const static inline TempTapeFactory FILETAPE_FACTORY =
-    [](size_t cells) -> unique_ptr<Tape> {
+    [](size_t cells) -> std::unique_ptr<Tape> {
     return std::make_unique<FileTape>(FileTape(cells));
 };
 
diff --git a/src/filetape.cpp b/src/filetape.cpp
index 42ea745..1235058 100644
--- a/src/filetape.cpp
+++ b/src/filetape.cpp
@@ -1,36 +1,43 @@
 #include "tapelib/filetape.h"
+#include <array>
 #include <cstddef>
+#include <cstdint>
 #include <filesystem>
 #include <fstream>
 #include <iomanip>
 #include <iostream>
+#include <sstream>
 #include <string>
 #include <thread>
+#include <vector>
 
 using std::fstream;
+using std::setfill;
+using std::setw;
+using std::string;
+using std::to_string;
+using std::this_thread::sleep_for;
 using tape::FileTape;
 
 std::string generate_tmp_file_name() {
     std::array<char, L_tmpnam> tmp_file_name{};
-    // tmpnam is unsafe, but its cross-platform
     std::tmpnam(tmp_file_name.data());
     return tmp_file_name.data();
 }
 
-FileTape::FileTape(const std::string file_name, const FileTapeSettings settings)
+FileTape::FileTape(const string file_name, const FileTapeSettings settings)
     : settings(settings), file_name(file_name) {
     this->file = fstream(file_name);
 }
 
-FileTape::FileTape(const size_t cells, const std::string file_name,
+FileTape::FileTape(const size_t cells, const string file_name,
                    const FileTapeSettings settings)
     : FileTape(file_name, settings) {
     this->file =
         fstream(this->file_name, fstream::in | fstream::out | fstream::trunc);
-    this->file << std::setfill('0') << std::setw(tape::FT_CELL_SIZE) << '0';
+    this->file << setfill('0') << setw(FT_CELL_SIZE) << '0';
     for (size_t i = 1; i < cells; i++) {
-        this->file << FT_DELIMETER << std::setfill('0')
-                   << std::setw(FT_CELL_SIZE) << '0';
+        this->file << FT_DELIMETER << setfill('0') << setw(FT_CELL_SIZE) << '0';
     }
     this->file.seekg(0, fstream::beg);
 }
@@ -40,22 +47,21 @@ FileTape::FileTape(const size_t cells, const FileTapeSettings settings)
     this->tmp = true;
 }
 
-FileTape::FileTape(FileTape &same_size_as, const std::string file_name,
+FileTape::FileTape(FileTape &same_size_as, const string file_name,
                    const FileTapeSettings settings)
     : settings(settings), file_name(file_name) {
     this->file =
         fstream(this->file_name, fstream::in | fstream::out | fstream::trunc);
-    this->file << std::setfill('0') << std::setw(tape::FT_CELL_SIZE) << '0';
+    this->file << setfill('0') << setw(tape::FT_CELL_SIZE) << '0';
     while (same_size_as.seek_forward()) {
-        file << tape::FT_DELIMETER << std::setfill('0')
-             << std::setw(tape::FT_CELL_SIZE) << '0';
+        file << FT_DELIMETER << setfill('0') << setw(FT_CELL_SIZE) << '0';
     }
     this->file.seekg(0, fstream::beg);
     same_size_as.file.seekg(0, fstream::beg);
 }
 
 FileTape::FileTape(FileTape &same_size_as, const FileTapeSettings settings)
-    : tape::FileTape(same_size_as, generate_tmp_file_name(), settings) {
+    : FileTape(same_size_as, generate_tmp_file_name(), settings) {
     this->tmp = true;
 }
 
@@ -68,17 +74,16 @@ FileTape::FileTape(const std::vector<uint32_t> &data,
     if (data.empty()) {
         return;
     }
-    this->file << std::setfill('0') << std::setw(FT_CELL_SIZE)
-               << std::to_string(data[0]);
+    this->file << setfill('0') << setw(FT_CELL_SIZE) << to_string(data[0]);
     for (size_t i = 1; i < data.size(); i++) {
-        this->file << FT_DELIMETER << std::setfill('0')
-                   << std::setw(FT_CELL_SIZE) << std::to_string(data[i]);
+        this->file << FT_DELIMETER << setfill('0') << setw(FT_CELL_SIZE)
+                   << to_string(data[i]);
     }
     this->file.seekg(0, fstream::beg);
 }
 
 bool FileTape::seek_backwards() {
-    std::this_thread::sleep_for(this->settings.seek_backwards_delay);
+    sleep_for(this->settings.seek_backwards_delay);
     if (this->file.tellg() == 0) {
         return false;
     }
@@ -87,7 +92,7 @@ bool FileTape::seek_backwards() {
 }
 
 bool FileTape::seek_forward() {
-    std::this_thread::sleep_for(this->settings.seek_forward_delay);
+    sleep_for(this->settings.seek_forward_delay);
     this->file.seekg(FT_SEEK_OFFSET, fstream::cur);
     this->file.peek(); // peek to check if eof is reached
     if (this->file.eof()) {
@@ -99,7 +104,7 @@ bool FileTape::seek_forward() {
 }
 
 uint32_t FileTape::read() {
-    std::this_thread::sleep_for(this->settings.read_delay);
+    sleep_for(this->settings.read_delay);
     uint32_t data = 0;
     this->file >> data;
     if (this->file.eof()) {
@@ -112,10 +117,9 @@ uint32_t FileTape::read() {
 }
 
 void FileTape::write(const uint32_t data) {
-    std::this_thread::sleep_for(this->settings.write_delay);
+    sleep_for(this->settings.write_delay);
     std::stringstream cell;
-    cell << std::setfill('0') << std::setw(FT_CELL_SIZE)
-         << std::to_string(data);
+    cell << setfill('0') << setw(FT_CELL_SIZE) << to_string(data);
     this->file.write(cell.str().data(), FT_CELL_SIZE);
     this->file.seekg(-FT_SEEK_OFFSET + 1, fstream::cur);
 }
diff --git a/src/tape_util.cpp b/src/tape_util.cpp
index 42e175e..1b8b1c1 100644
--- a/src/tape_util.cpp
+++ b/src/tape_util.cpp
@@ -1,5 +1,11 @@
 #include "tapelib/tape_util.h"
+#include "tapelib/tape.h"
 #include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <vector>
 
 using std::unique_ptr;
 using std::vector;
diff --git a/tests/filetape_sort_tests.cpp b/tests/filetape_sort_tests.cpp
index 7f2e001..0053d52 100644
--- a/tests/filetape_sort_tests.cpp
+++ b/tests/filetape_sort_tests.cpp
@@ -1,14 +1,21 @@
+#include "tapelib/filetape.h"
+#include "tapelib/tape.h"
 #include "tapelib/tape_util.h"
 #include <algorithm>
 #include <catch2/catch_test_macros.hpp>
+#include <cstdint>
+#include <vector>
 
-const static std::vector<uint32_t> TEST_DATA = {123, 26, 87, 266, 111, 234,
-                                                6,   63, 28, 1,   90,  33};
-const static std::vector<uint32_t> TEST_DATA_SORTED = {
-    1, 6, 26, 28, 33, 63, 87, 90, 111, 123, 234, 266};
+using std::vector;
+using namespace tape;
 
-std::vector<uint32_t> read_from_tape_backwards(tape::Tape &tape) {
-    std::vector<uint32_t> data;
+const static vector<uint32_t> TEST_DATA = {123, 26, 87, 266, 111, 234,
+                                           6,   63, 28, 1,   90,  33};
+const static vector<uint32_t> TEST_DATA_SORTED = {1,  6,  26,  28,  33,  63,
+                                                  87, 90, 111, 123, 234, 266};
+
+vector<uint32_t> read_from_tape_backwards(Tape &tape) {
+    vector<uint32_t> data;
     do {
         data.push_back(tape.read());
     } while (tape.seek_backwards());
@@ -16,40 +23,39 @@ std::vector<uint32_t> read_from_tape_backwards(tape::Tape &tape) {
     return data;
 }
 
-// NOLINTBEGIN(*-magic-numbers)
+// NOLINTBEGIN
 TEST_CASE("Sorting FileTape with external sort", "[sort]") {
-    tape::FileTape input(TEST_DATA);
-    tape::FileTape output(input);
+    FileTape input(TEST_DATA);
+    FileTape output(input);
 
     SECTION("Sorting with no limitations") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY);
+        external_sort(input, output, FILETAPE_FACTORY);
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 
     SECTION("Sorting with 4 elements in memory limit") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY, 4);
+        external_sort(input, output, FILETAPE_FACTORY, 4);
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 
     SECTION("Sorting with 9 elements in memory limit") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY, 9);
+        external_sort(input, output, FILETAPE_FACTORY, 9);
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 
     SECTION("Sorting with vector size elements in memory limit") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY,
-                            TEST_DATA.size());
+        external_sort(input, output, FILETAPE_FACTORY, TEST_DATA.size());
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 
     SECTION("Sorting with 1000 elements in memory limit") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY, 1000);
+        external_sort(input, output, FILETAPE_FACTORY, 1000);
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 
     SECTION("Sorting with 1 elements in memory limit") {
-        tape::external_sort(input, output, tape::FILETAPE_FACTORY, 1);
+        external_sort(input, output, FILETAPE_FACTORY, 1);
         REQUIRE(read_from_tape_backwards(output) == TEST_DATA_SORTED);
     }
 }
-// NOLINTEND(*-magic-numbers)
+// NOLINTEND
diff --git a/tests/filetape_tests.cpp b/tests/filetape_tests.cpp
index 2c69ed6..e8f8e09 100644
--- a/tests/filetape_tests.cpp
+++ b/tests/filetape_tests.cpp
@@ -1,13 +1,16 @@
 #include "tapelib/filetape.h"
 #include <catch2/catch_test_macros.hpp>
+#include <cstdint>
 #include <vector>
 
-const static std::vector<uint32_t> TEST_DATA = {1, 12345, 0, 2222222222,
-                                                4294967295};
+using std::vector;
+using namespace tape;
 
-// NOLINTBEGIN(readability-function-cognitive-complexity)
+const static vector<uint32_t> TEST_DATA = {1, 12345, 0, 2222222222, 4294967295};
+
+// NOLINTBEGIN
 TEST_CASE("Reading data from a FileTape", "[filetape]") {
-    tape::FileTape tape(TEST_DATA);
+    FileTape tape(TEST_DATA);
 
     SECTION("Read all data sequentially") {
         REQUIRE(tape.read() == TEST_DATA[0]);
@@ -38,7 +41,7 @@ TEST_CASE("Reading data from a FileTape", "[filetape]") {
 }
 
 TEST_CASE("Seeking forward and backwards", "[filetape]") {
-    tape::FileTape tape(TEST_DATA);
+    FileTape tape(TEST_DATA);
 
     SECTION("Rewinding at the beginning of a file tape") {
         REQUIRE(tape.seek_backwards() == false);
@@ -67,7 +70,7 @@ TEST_CASE("Seeking forward and backwards", "[filetape]") {
 }
 
 TEST_CASE("Writing to a file tape", "[filetape]") {
-    tape::FileTape tape(3);
+    FileTape tape(3);
 
     tape.write(0);
     REQUIRE(tape.read() == 0);
@@ -83,4 +86,4 @@ TEST_CASE("Writing to a file tape", "[filetape]") {
     tape.write(4);
     REQUIRE(tape.read() == 4);
 }
-// NOLINTEND(readability-function-cognitive-complexity)
+// NOLINTEND
diff --git a/tests/generate_input.cpp b/tests/generate_input.cpp
index 4d12e3a..7426037 100644
--- a/tests/generate_input.cpp
+++ b/tests/generate_input.cpp
@@ -6,6 +6,12 @@
 #include <iostream>
 #include <string>
 
+using std::setfill;
+using std::setw;
+using std::string;
+using std::to_string;
+using namespace tape;
+
 /**
  * Generate big input data sets for external sort testing.
  * Takes 2 positional arguments - first one is the ouput file name,
@@ -17,7 +23,7 @@ int main(int argc, char *argv[]) {
         std::cerr << "Not enough arguments" << std::endl;
         return -1;
     }
-    std::string out_name = argv[1];    // NOLINT
+    string out_name = argv[1];         // NOLINT
     size_t cells = std::stoi(argv[2]); // NOLINT
     std::ofstream out(out_name);
     if (!out.is_open()) {
@@ -25,11 +31,10 @@ int main(int argc, char *argv[]) {
         return -1;
     }
     srand(time(nullptr));
-    out << std::setfill('0') << std::setw(tape::FT_CELL_SIZE)
-        << std::to_string(rand());
+    out << setfill('0') << setw(tape::FT_CELL_SIZE) << to_string(rand());
     for (size_t i = 1; i < cells; i++) {
-        out << tape::FT_DELIMETER << std::setfill('0')
-            << std::setw(tape::FT_CELL_SIZE) << std::to_string(rand());
+        out << FT_DELIMETER << setfill('0') << setw(tape::FT_CELL_SIZE)
+            << to_string(rand());
     }
     return 0;
 }