OpenTracks/src/androidTest/java/de/dennisguse/opentracks/sensors/UintUtilsTest.java

package de.dennisguse.opentracks.sensors;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThrows;

import org.junit.Test;

public class UintUtilsTest {

    @Test
    public void diff_uint16_valid() {
        assertEquals(0, UintUtils.diff(1, 1, UintUtils.UINT16_MAX));
        assertEquals(1, UintUtils.diff(2, 1, UintUtils.UINT16_MAX));
        assertEquals(3, UintUtils.diff(5, 2, UintUtils.UINT16_MAX));
        assertEquals(65535, UintUtils.diff(1, 2, UintUtils.UINT16_MAX));     /* unsigned 16 arithmetic is modulo UINT16_MAX + 1, not modulo UINT16_MAX */
        assertEquals(65530, UintUtils.diff(UintUtils.UINT16_MAX, 5, UintUtils.UINT16_MAX));
    }

    @Test
    public void diff_uint16_invalid() {
        /*   Test modulo arithmetic for arguments that are out of range */
        assertThrows(RuntimeException.class, () -> UintUtils.diff(65537, 1, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(1, 65537, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(65537, 65537, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-65535, 1, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(1, -65535, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-65535, -65535, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-65535, 65537, UintUtils.UINT16_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(65537, -65535, UintUtils.UINT16_MAX));
    }

    @Test
    public void diff_uint32() {
        assertEquals(0, UintUtils.diff(1, 1, UintUtils.UINT32_MAX));
        assertEquals(1, UintUtils.diff(2, 1, UintUtils.UINT32_MAX));
        assertEquals(3, UintUtils.diff(5, 2, UintUtils.UINT32_MAX));
        assertEquals(4294967295L, UintUtils.diff(1, 2, UintUtils.UINT32_MAX));
        assertEquals(4294967290L, UintUtils.diff(UintUtils.UINT32_MAX, 5, UintUtils.UINT32_MAX));
    }

    @Test
    public void diff_unint32_invalid() {
        /*   Test modulo arithmetic for arguments that are out of range */
        assertThrows(RuntimeException.class, () -> UintUtils.diff(4294967297L, 1, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(1, 4294967297L, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(4294967297L, 4294967297L, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-4294967295L, 1, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(1, -4294967295L, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-4294967295L, -4294967295L, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(-4294967295L, 4294967297L, UintUtils.UINT32_MAX));
        assertThrows(RuntimeException.class, () -> UintUtils.diff(65537, -4294967297L, UintUtils.UINT32_MAX));
    }

    @Test
    public void realData() {
        assertEquals(1, UintUtils.diff(381616, 381615, UintUtils.UINT32_MAX));
    }
}