mathjs/test/function/probability/permutations.test.js

66 lines
2.8 KiB
JavaScript

var assert = require('assert'),
error = require('../../../lib/error/index'),
math = require('../../../index'),
permutations = math.permutations;
describe('permutations', function() {
it('should calculate the permutations of a number', function() {
assert.equal(permutations(0), 1);
assert.equal(permutations(1), 1);
assert.equal(permutations(2), 2);
assert.equal(permutations(3), 6);
assert.equal(permutations(4), 24);
assert.equal(permutations(5), 120);
});
it('should calculate the permutations of a BigNumber', function() {
assert.deepEqual(permutations(math.bignumber(4)), math.bignumber(24));
assert.deepEqual(permutations(math.bignumber(5)), math.bignumber(120));
assert.deepEqual(permutations(math.bignumber(8)), math.bignumber(40320));
});
it('should calculate the permutations of a BigNumber, taking k at a time', function() {
assert.deepEqual(permutations(math.bignumber(5), math.bignumber(4)), math.bignumber(120));
assert.deepEqual(permutations(math.bignumber(6), math.bignumber(3)), math.bignumber(120));
assert.deepEqual(permutations(math.bignumber(9), math.bignumber(8)), math.bignumber(362880));
});
it('should calculate the permutations of a number, taking k at a time', function() {
assert.equal(permutations(5, 4), 120);
assert.equal(permutations(9, 8), 362880);
assert.equal(permutations(7, 5), 2520);
});
it('should fail loudly when k is larger than x', function() {
assert.throws(function(){permutations(5, 6);}, TypeError);
assert.throws(function(){permutations(math.bignumber(5), math.bignumber(6));}, TypeError);
});
it('should not accept negative or non-integer arguments', function() {
assert.throws(function(){permutations(12, -6);}, TypeError);
assert.throws(function(){permutations(-12, 6);}, TypeError);
assert.throws(function(){permutations(4.5, 2);}, TypeError);
assert.throws(function(){permutations(4, 0.5);}, TypeError);
assert.throws(function(){permutations(math.bignumber(-12), -6);}, TypeError);
assert.throws(function(){permutations(math.bignumber(12.5), math.bignumber(6));}, TypeError);
assert.throws(function(){permutations(math.bignumber(12.5), math.pi);}, TypeError);
});
it('should not accept more than two arguments', function() {
assert.throws(function(){permutations(12, 6, 13);});
assert.throws(function(){permutations(-12, 6, 13);});
});
it('should not accept arguments of the wrong type', function() {
assert.throws(function(){permutations("baa baa black sheep", true);});
assert.throws(function(){permutations(new Array(12));});
});
it('should LaTeX permutations', function () {
var expression = math.parse('permutations(2)');
assert.equal(expression.toTex(), '\\mathrm{permutations}\\left(2\\right)');
});
});