diff --git a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java b/src/main/java/com/thealgorithms/maths/FactorialRecursion.java index 85e03c4dd1a4..d9bafd1e39e9 100644 --- a/src/main/java/com/thealgorithms/maths/FactorialRecursion.java +++ b/src/main/java/com/thealgorithms/maths/FactorialRecursion.java @@ -1,16 +1,8 @@ package com.thealgorithms.maths; -public class FactorialRecursion { - - /* Driver Code */ - public static void main(String[] args) { - assert factorial(0) == 1; - assert factorial(1) == 1; - assert factorial(2) == 2; - assert factorial(3) == 6; - assert factorial(5) == 120; +public final class FactorialRecursion { + private FactorialRecursion() { } - /** * Recursive FactorialRecursion Method * diff --git a/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java b/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java new file mode 100644 index 000000000000..db18b46356b4 --- /dev/null +++ b/src/test/java/com/thealgorithms/maths/FactorialRecursionTest.java @@ -0,0 +1,27 @@ +package com.thealgorithms.maths; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertThrows; + +import java.util.stream.Stream; +import org.junit.jupiter.api.Test; +import org.junit.jupiter.params.ParameterizedTest; +import org.junit.jupiter.params.provider.Arguments; +import org.junit.jupiter.params.provider.MethodSource; + +public class FactorialRecursionTest { + @ParameterizedTest + @MethodSource("inputStream") + void testFactorialRecursion(long expected, int number) { + assertEquals(expected, FactorialRecursion.factorial(number)); + } + + private static Stream inputStream() { + return Stream.of(Arguments.of(1, 0), Arguments.of(1, 1), Arguments.of(2, 2), Arguments.of(6, 3), Arguments.of(120, 5)); + } + + @Test + void testThrowsForNegativeInput() { + assertThrows(IllegalArgumentException.class, () -> FactorialRecursion.factorial(-1)); + } +}