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42 lines
1.4 KiB
JavaScript
42 lines
1.4 KiB
JavaScript
var assert = require('assert'),
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math = require('../../../index')(),
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permutations = math.permutations;
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describe('permutations', function() {
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it('should calculate the permutations of a number', function() {
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assert.equal(permutations(0), 1);
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assert.equal(permutations(1), 1);
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assert.equal(permutations(2), 2);
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assert.equal(permutations(3), 6);
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assert.equal(permutations(4), 24);
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assert.equal(permutations(5), 120);
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});
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it('should calculate the permutations of a number, taking k at a time', function() {
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assert.equal(permutations(5, 4), 120);
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assert.equal(permutations(9, 8), 362880);
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assert.equal(permutations(7, 5), 2520);
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});
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it('should fail loudly when k is larger than x', function() {
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assert.throws(function(){permutations(5, 6);}, TypeError);
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});
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it('should not accept negative or non-integer arguments', function() {
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assert.throws(function(){permutations(12, -6);}, TypeError);
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assert.throws(function(){permutations(-12, -6);}, TypeError);
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});
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it('should not accept more than two arguments', function() {
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assert.throws(function(){permutations(12, 6, 13);});
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assert.throws(function(){permutations(-12, 6, 13);});
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});
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it('should not accept arguments of the wrong type', function() {
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assert.throws(function(){permutations("baa baa black sheep", true);});
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assert.throws(function(){permutations(new Array(12));});
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});
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});
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