CatalanNumbersTest.java

packagecom.thealgorithms.maths;

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

importjava.util.stream.Stream;
importorg.junit.jupiter.api.Test;
importorg.junit.jupiter.params.ParameterizedTest;
importorg.junit.jupiter.params.provider.MethodSource;

/**
 * Test class for CatalanNumbers
 */
classCatalanNumbersTest {

/**
 * Provides test data for the parameterized Catalan number test.
 * Each array contains two elements:
 * [input number, expected Catalan number for that input]
 */
staticStream<Object[]> catalanNumbersProvider() {
returnStream.of(newObject[] {0, 1}, newObject[] {1, 1}, newObject[] {2, 2}, newObject[] {3, 5}, newObject[] {4, 14}, newObject[] {5, 42}, newObject[] {6, 132}, newObject[] {7, 429}, newObject[] {8, 1430}, newObject[] {9, 4862}, newObject[] {10, 16796});
 }

/**
 * Parameterized test for checking the correctness of Catalan numbers.
 * Uses the data from the provider method 'catalanNumbersProvider'.
 */
@ParameterizedTest
@MethodSource("catalanNumbersProvider")
voidtestCatalanNumbers(intinput, intexpected) {
assertEquals(expected, CatalanNumbers.catalan(input), () -> String.format("Catalan number for input %d should be %d", input, expected));
 }

/**
 * Test for invalid inputs which should throw an IllegalArgumentException.
 */
@Test
voidtestIllegalInput() {
assertThrows(IllegalArgumentException.class, () -> CatalanNumbers.catalan(-1));
assertThrows(IllegalArgumentException.class, () -> CatalanNumbers.catalan(-5));
 }
}