ardupilot/libraries/AP_NavEKF/tests/test_ring_buffer.cpp

#include <AP_gtest.h>

/*
  tests for AP_NavEKF/EKF_Buffer.cpp
 */

#include <AP_NavEKF/EKF_Buffer.h>
#include <stdlib.h>

#if CONFIG_HAL_BOARD == HAL_BOARD_SITL || CONFIG_HAL_BOARD == HAL_BOARD_LINUX

TEST(EKF_Buffer, EKF_Buffer)
{
    struct test_data : EKF_obs_element_t {
        uint32_t data;
    };
    EKF_obs_buffer_t<test_data> buf;
    buf.init(8);
    struct test_data d, d2;
    uint32_t now = 100;
    d.data = 17;
    d.time_ms = now++;
    buf.push(d);

    EXPECT_TRUE(buf.recall(d2, now));
    EXPECT_EQ(d2.data, d.data);
    EXPECT_EQ(d2.time_ms, uint32_t(100));

    d.time_ms = 101;
    buf.push(d);
    d.time_ms = 102;
    buf.push(d);

    // recall first element
    EXPECT_TRUE(buf.recall(d2, 101));
    EXPECT_EQ(d2.data, d.data);
    EXPECT_EQ(d2.time_ms, uint32_t(101));

    EXPECT_TRUE(buf.recall(d2, 102));
    EXPECT_EQ(d2.data, d.data);
    EXPECT_EQ(d2.time_ms, uint32_t(102));

    EXPECT_FALSE(buf.recall(d2, 103));

    d.time_ms = 101;
    buf.push(d);
    d.time_ms = 102;
    buf.push(d);

    // recall 2nd element, note that first element is discarded
    EXPECT_TRUE(buf.recall(d2, 103));
    EXPECT_EQ(d2.data, d.data);
    EXPECT_EQ(d2.time_ms, uint32_t(102));

    EXPECT_FALSE(buf.recall(d2, 103));
    EXPECT_FALSE(buf.recall(d2, 103));

    // test overflow of buffer
    for (uint8_t i=0; i<16; i++) {
        d.time_ms = 100+i;
        d.data = 1000+i;
        buf.push(d);
    }
    for (uint8_t i=0; i<16; i++) {
        if (i < 8) {
            EXPECT_TRUE(buf.recall(d2, 108+i));
        } else {
            EXPECT_FALSE(buf.recall(d2, 1100));
        }
    }

    // test with an element that is too old
    d.time_ms = 101;
    d.data = 200;
    buf.push(d);
    d.time_ms = 1002;
    d.data = 2000;
    buf.push(d);

    // recall element, first one is too old so will be discarded
    EXPECT_TRUE(buf.recall(d2, 1003));
    EXPECT_EQ(d2.data, 2000U);
    EXPECT_EQ(d2.time_ms, uint32_t(1002));

    EXPECT_FALSE(buf.recall(d2, 103));


    // test 32 bit time wrap
    d.time_ms = 0xFFFFFFF0U;
    d.data = 200;
    buf.push(d);
    d.time_ms = 0xFFFFFFFAU;
    d.data = 2000;
    buf.push(d);
    d.time_ms = 0xFFFFFFFBU;
    d.data = 2001;
    buf.push(d);

    // recall element, first one is too old so will be discarded
    EXPECT_TRUE(buf.recall(d2, 10));
    EXPECT_EQ(d2.data, 2001U);
    EXPECT_EQ(d2.time_ms, uint32_t(0xFFFFFFFBU));

    EXPECT_FALSE(buf.recall(d2, 103));

    // test 32 bit time wrap with a too old element
    d.time_ms = 0xFFFFFFFFU - 1000U;
    d.data = 200;
    buf.push(d);
    d.time_ms = 0xFFFFFFFBU;
    d.data = 2001;
    buf.push(d);

    // recall element, first one is too old so will be discarded
    EXPECT_TRUE(buf.recall(d2, 10));
    EXPECT_EQ(d2.data, 2001U);
    EXPECT_EQ(d2.time_ms, uint32_t(0xFFFFFFFBU));

    EXPECT_FALSE(buf.recall(d2, 103));
}

AP_GTEST_MAIN()

#endif // HAL_SITL or HAL_LINUX