import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.Test;

class InversionCountTest {

	@Test
	void testInversionCount0() {
		int[] a = {2, 3, 9, 2, 9};
		assertEquals(2, InversionCount.getInversionCountFromArray(a));
	}

	@Test
	void testInversionCount1() {
		int[] a = {1, 1, 1, 1, 1};
		assertEquals(0, InversionCount.getInversionCountFromArray(a));
	}

	@Test
	void testInversionCount2() {
		int[] a = {6, 5, 4, 3, 2, 1};
		assertEquals(15, InversionCount.getInversionCountFromArray(a));
	}

	@Test
	void testInversionCount3() {
		int[] a = {1, 1, 1, 2, 1};
		assertEquals(1, InversionCount.getInversionCountFromArray(a));
	}

	@Test
	void testInversionCount4() {
		int[] a = {2, 1, 1};
		assertEquals(2, InversionCount.getInversionCountFromArray(a));
	}

	@Test
	void testMergeSort0() {
		int[] a = {2, 3, 9, 2, 9};
		int[] b = {2, 2, 3, 9, 9};
		assertArrayEquals(b, InversionCount.mergeSortArray(a));
	}

	@Test
	void testMergeSort1() {
		int[] a = {5, 4, 3, 2, 1};
		int[] b = {1, 2, 3, 4, 5};
		assertArrayEquals(b, InversionCount.mergeSortArray(a));
	}
}