MultipleArbitraryPrecisionIntegersTest.java

import org.junit.Test;

import java.util.Arrays;
import java.util.List;

import static org.junit.Assert.assertEquals;

public class MultipleArbitraryPrecisionIntegersTest {

    List<Integer> expected;
    List<Integer> a;
    List<Integer> b;

    @Test
    public void multiply1() {
        expected = Arrays.asList(0);
        a = Arrays.asList(0);
        b = Arrays.asList(1, 1, 1);

        test(expected, a, b);
    }

    @Test
    public void multiply2() {
        expected = Arrays.asList(1, 4, 4);
        a = Arrays.asList(1, 2);
        b = Arrays.asList(1, 2);

        test(expected, a, b);
    }

    @Test
    public void multiply3() {
        expected = Arrays.asList(-1, 4, 7, 5 ,7, 3, 9, 5, 2, 5, 8, 9, 6, 7, 6, 4, 1, 2, 9, 2, 7);
        a = Arrays.asList(1, 9, 3, 7, 0, 7, 7, 2, 1);
        b = Arrays.asList(-7, 6, 1, 8, 3, 8, 2, 5, 7, 2, 8, 7);

        test(expected, a, b);
    }

    private void test(List<Integer> expected, List<Integer> a, List<Integer> b) {
        assertEquals(expected, MultipleArbitraryPrecisionIntegers.multiply(a,b));
    }

}