etl/test/test_debounce_value.cpp

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com

Copyright(c) 2026 John Wellbelove

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#include "unit_test_framework.h"

#include "etl/debounce_value.h"

#include <vector>

namespace
{
  SUITE(test_debounce)
  {
    //*************************************************************************
    TEST(test_debounce_value)
    {
      const uint8_t Initial_Value = 1;
      const uint8_t Stable_Count  = 4;

      etl::debounce_value<uint8_t, uint8_t> value(Initial_Value, Stable_Count);

      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      //*******************************
      // Transition from unstable to stable.
      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      // Stable & changed.
      CHECK_TRUE(value.update(2));
      CHECK_TRUE(value.is_stable());
      CHECK_TRUE(value.has_changed());
      CHECK_EQUAL(2, value.get());

      // Still stable.
      CHECK_FALSE(value.update(2));
      CHECK_TRUE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      //*******************************
      // Transition from unstable to stable.
      // Unstable.
      CHECK_FALSE(value.update(3));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(3));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(3));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      // Stable & changed.
      CHECK_TRUE(value.update(3));
      CHECK_TRUE(value.is_stable());
      CHECK_TRUE(value.has_changed());
      CHECK_EQUAL(3, value.get());

      // Stable.
      CHECK_FALSE(value.update(3));
      CHECK_TRUE(value.is_stable());
      CHECK_FALSE(value.has_changed());
    }

    //*************************************************************************
    TEST(test_debounce_value_modify_stable_count)
    {
      const uint8_t Initial_Value = 1;
      const uint8_t Stable_Count  = 4;

      etl::debounce_value<uint8_t, uint8_t> value(Initial_Value, Stable_Count);

      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      //*******************************
      // Transition from unstable to stable.
      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      CHECK_FALSE(value.update(2));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      // Stable & changed.
      CHECK_TRUE(value.update(2));
      CHECK_TRUE(value.is_stable());
      CHECK_TRUE(value.has_changed());
      CHECK_EQUAL(2, value.get());

      // Still stable.
      CHECK_FALSE(value.update(2));
      CHECK_TRUE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      //*******************************
      // Change the stable count.
      value.set_stable_count(2);

      //*******************************
      // Transition from unstable to stable.
      // Unstable.
      CHECK_FALSE(value.update(3));
      CHECK_FALSE(value.is_stable());
      CHECK_FALSE(value.has_changed());

      // Stable & changed.
      CHECK_TRUE(value.update(3));
      CHECK_TRUE(value.is_stable());
      CHECK_TRUE(value.has_changed());
      CHECK_EQUAL(3, value.get());

      // Stable.
      CHECK_FALSE(value.update(3));
      CHECK_TRUE(value.is_stable());
      CHECK_FALSE(value.has_changed());
    }

    //*************************************************************************
    TEST(test_debounce_values_from_an_input_stream)
    {
      std::vector<uint8_t> input = {1, 2, 3, 3, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6};
      std::vector<uint8_t> output;
      std::vector<uint8_t> expected = {2, 3, 4, 6};

      const uint8_t                         Stable_Count = 3;
      etl::debounce_value<uint8_t, uint8_t> value(0, Stable_Count);

      for (uint8_t v : input)
      {
        if (value.update(v))
        {
          output.push_back(value.get());
        }
      }

      CHECK_EQUAL(expected.size(), output.size());
      CHECK_ARRAY_EQUAL(expected.data(), output.data(), expected.size());
    }
  }
} // namespace