skullc-peripherals/Utility/Tests/ringbuffer.cpp

//
// Created by erki on 13.03.21.
//

#include <catch2/catch.hpp>

#include "utility_ringbuffer.hpp"

template<size_t N>
using Ringbuffer = Utility::Ringbuffer<int, N>;

TEST_CASE("Ringbuffer iterator", "[ringbuffer],[iterator]")
{
  using iterator = Ringbuffer<10>::iterator;
  const auto begin = iterator::pointer(10);
  const auto end = iterator::pointer(21);
  iterator it = iterator(iterator::pointer(15), begin, end);

  SECTION("Incrementing postfix increases its pointer and returns initial.")
  {
    iterator it_second = it++;
    REQUIRE(it - it_second == iterator::difference_type(1));
  }

  SECTION("Incrementing prefix increases its pointer and returns new.")
  {
    const iterator original = it;
    iterator it_second = ++it;
    REQUIRE(it_second == it);
    REQUIRE(it - original == iterator::difference_type(1));
  }

  SECTION("Subtracting 1 decreases its pointer.")
  {
    iterator it_second = it - 1;
    REQUIRE(it - it_second == iterator::difference_type(1));
  }

  SECTION("Adding 1 increases its pointer.")
  {
    iterator it_second = it + 1;
    REQUIRE(it_second - it == iterator::difference_type(1));
  }
}

TEST_CASE("Ringbuffer iterator at the end", "[ringbuffer],[iterator]")
{
  using iterator = Ringbuffer<10>::iterator;
  const auto begin = iterator::pointer(10);
  const auto end = iterator::pointer(21);
  iterator it = iterator(end - 1, begin, end);

  const auto it_begin = iterator(begin, begin, end);

  SECTION("Incrementing postfix sets the pointer to begin().")
  {
    it++;
    REQUIRE(it == it_begin);
  }

  SECTION("Incrementing prefix sets the pointer to begin().")
  {
    ++it;
    REQUIRE(it == it_begin);
  }

  SECTION("Adding 1 sets the pointer to begin().")
  {
    const iterator it_second = it + 1;
    REQUIRE(it_second == it_begin);
  }
}

TEST_CASE("Ringbuffer iterator at the beginning", "[ringbuffer],[iterator]")
{
  using iterator = Ringbuffer<10>::iterator;
  const auto begin = iterator::pointer(10);
  const auto end = iterator::pointer(21);
  iterator it = iterator(begin, begin, end);

  const auto it_last = iterator(end - 1, begin, end);

  SECTION("Subtracting 1 sets the pointer to last element.")
  {
    const iterator it_second = it - 1;
    REQUIRE(it_last == it_second);
  }
}

TEST_CASE("Constructed buffer is empty.", "[ringbuffer]")
{
  Ringbuffer<10> buffer;

  REQUIRE(buffer.begin() == buffer.end());
  REQUIRE(buffer.size() == 0);
  REQUIRE(buffer.empty());
}

TEST_CASE("Adding single element.", "[ringbuffer]")
{
  Ringbuffer<10> buffer;
  const auto old_end = buffer.end();
  const auto old_begin = buffer.begin();

  buffer.push_back(1);

  SECTION("Increases size and empty appropriately.")
  {
    REQUIRE(buffer.size() == 1);
    REQUIRE(!buffer.empty());
  }

  SECTION("Updates end() appropriately.")
  {
    REQUIRE(old_end != buffer.end());
  }

  SECTION("begin() remains the same.")
  {
    REQUIRE(old_begin == buffer.begin());
  }

  SECTION("Makes begin() refer to the inserted member.")
  {
    REQUIRE(*old_begin == 1);
    REQUIRE(*buffer.begin() == 1);
  }

  SECTION("Distance between begin and end is 1.")
  {
    REQUIRE(buffer.end() - buffer.begin() == 1);
  }

  SECTION("Makes back() refer to the first element.")
  {
    REQUIRE(buffer.back() == 1);
  }

  SECTION("Makes front() refer to the first element.")
  {
    REQUIRE(buffer.front() == 1);
  }

  SECTION("Makes front() and back() refer to the same memory address.")
  {
    REQUIRE(&buffer.front() == &buffer.back());
  }
}

TEST_CASE("Adding multiple elements.", "[ringbuffer]")
{
  Ringbuffer<10> buffer;
  const auto old_begin = buffer.begin();

  buffer.push_back(1);
  buffer.push_back(2);
  buffer.push_back(3);

  SECTION("Increases size and empty appropriately.")
  {
    REQUIRE(buffer.size() == 3);
    REQUIRE(!buffer.empty());
  }

  SECTION("Makes front() refer to the first element.")
  {
    REQUIRE(buffer.front() == 1);
  }

  SECTION("Makes back() refer to the last element.")
  {
    REQUIRE(buffer.back() == 3);
  }

  SECTION("Updates begin() and end() appropriately.")
  {
    REQUIRE(old_begin == buffer.begin());
    REQUIRE(buffer.end() - buffer.begin() == 3);
  }
}

TEST_CASE("Removing elements from the ringbuffer.", "[ringbuffer]")
{
  Ringbuffer<10> buffer;
  const auto old_begin = buffer.begin();

  buffer.push_back(1);
  buffer.push_back(2);
  buffer.push_back(3);

  buffer.pop_front();

  SECTION("Updates the front() appropriately.")
  {
    REQUIRE(buffer.front() == 2);
  }

  SECTION("Updates begin() appropriately.")
  {
    REQUIRE(buffer.begin() - old_begin == 1);
  }

  SECTION("Updates size() appropriately.")
  {
    REQUIRE(buffer.size() == 2);
  }

  SECTION("Erasing remaining elements")
  {
    buffer.pop_front();
    buffer.pop_front();

    SECTION("Updates empty() appropriately.")
    {
      REQUIRE(buffer.empty());
    }

    SECTION("Updates begin() and end() appropriately.")
    {
      REQUIRE(buffer.begin() == buffer.end());
    }

    SECTION("Updates size() appropriately.")
    {
      REQUIRE(buffer.size() == 0);
    }
  }
}

TEST_CASE("Clearing a ringbuffer works.", "[ringbuffer]")
{
  Ringbuffer<10> buffer;

  buffer.push_back(1);
  buffer.push_back(2);
  buffer.push_back(3);

  buffer.clear();

  SECTION("Updates size() and empty() appropriately.")
  {
    REQUIRE(buffer.empty());
    REQUIRE(buffer.size() == 0);
  }

  SECTION("Sets begin() and end() pointers appropriately.")
  {
    REQUIRE(buffer.begin() == buffer.end());
  }
}