use use_combinatorics::{CombinatoricsError, combinations, factorial, permutations};
#[test]
fn direct_combinatorics_api_covers_basic_counting() -> Result<(), CombinatoricsError> {
assert_eq!(factorial(6)?, 720);
assert_eq!(permutations(6, 2)?, 30);
assert_eq!(combinations(6, 2)?, 15);
Ok(())
}
#[test]
fn direct_combinatorics_api_reports_invalid_inputs() {
assert_eq!(
combinations(2, 3),
Err(CombinatoricsError::KExceedsN { n: 2, k: 3 })
);
}