CollatzConjectureTest.java

packagecom.thealgorithms.maths;

importstaticorg.junit.jupiter.api.Assertions.assertEquals;
importstaticorg.junit.jupiter.api.Assertions.assertIterableEquals;
importstaticorg.junit.jupiter.api.Assertions.assertThrows;

importjava.util.List;
importorg.junit.jupiter.api.BeforeAll;
importorg.junit.jupiter.api.Test;

classCollatzConjectureTest {

staticCollatzConjecturecConjecture;

@BeforeAll
staticvoidsetUp() {
cConjecture = newCollatzConjecture();
 }

@Test
voidnextNumberFromEvenNumber() {
assertEquals(25, cConjecture.nextNumber(50));
 }

@Test
voidnextNumberFromOddNumber() {
assertEquals(154, cConjecture.nextNumber(51));
 }

@Test
voidcollatzConjecture() {
finalList<Integer> expected = List.of(35, 106, 53, 160, 80, 40, 20, 10, 5, 16, 8, 4, 2, 1);
assertIterableEquals(expected, cConjecture.collatzConjecture(35));
 }

@Test
voidsequenceOfNotNaturalFirstNumber() {
assertThrows(IllegalArgumentException.class, () -> cConjecture.collatzConjecture(0));
assertThrows(IllegalArgumentException.class, () -> cConjecture.collatzConjecture(-1));
 }
}