| 1 | var assert = require('assert');
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| 2 | var types = require('./types');
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| 3 |
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| 4 | var Either = require('..').Either;
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| 5 |
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| 6 | describe('Either', function() {
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| 7 | var e = Either('original left', 1);
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| 8 |
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| 9 | function mult(a) {
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| 10 | return function(b) { return a * b; };
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| 11 | }
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| 12 |
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| 13 | function add(a) {
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| 14 | return function(b) { return a + b; };
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| 15 | }
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| 16 |
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| 17 | it('is a Functor', function() {
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| 18 | var fTest = types.functor;
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| 19 | assert.equal(true, fTest.iface(e));
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| 20 | assert.equal(true, fTest.id(e));
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| 21 | assert.equal(true, fTest.compose(e, mult(2), add(3)));
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| 22 | });
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| 23 |
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| 24 | it('is an Apply', function() {
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| 25 | var aTest = types.apply;
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| 26 | var appA = Either('apply test fn a', mult(10));
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| 27 | var appU = Either('apply test fn u', add(5));
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| 28 | var appV = Either('apply test value v', 10);
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| 29 |
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| 30 | assert.equal(true, aTest.iface(appA));
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| 31 | assert.equal(true, aTest.compose(appA, appU, appV));
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| 32 | });
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| 33 |
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| 34 | it('is an Applicative', function() {
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| 35 | var aTest = types.applicative;
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| 36 | var app1 = Either('app1', 101);
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| 37 | var app2 = Either('app2', -123);
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| 38 | var appF = Either('appF', mult(3));
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| 39 |
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| 40 | assert.equal(true, aTest.iface(app1));
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| 41 | assert.equal(true, aTest.id(app1, app2));
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| 42 | assert.equal(true, aTest.homomorphic(app1, add(3), 46));
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| 43 | assert.equal(true, aTest.interchange(app1, appF, 17));
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| 44 | });
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| 45 |
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| 46 | it('is a Chain', function() {
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| 47 | var cTest = types.chain;
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| 48 | var f1 = function(x) {return Either('f1', (3 * x));};
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| 49 | var f2 = function(x) {return Either('f2', (5 + x));};
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| 50 |
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| 51 | assert.equal(true, cTest.iface(e));
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| 52 | assert.equal(true, cTest.associative(e, f1, f2));
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| 53 | });
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| 54 |
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| 55 | it('is a Monad', function() {
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| 56 | var mTest = types.monad;
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| 57 | assert.equal(true, mTest.iface(e));
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| 58 | });
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| 59 |
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| 60 | it('is an Extend', function() {
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| 61 | var eTest = types.extend;
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| 62 | var r = Either(null, 1);
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| 63 | var l = Either(1, null);
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| 64 | var f = function(x) {return x + 1;};
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| 65 |
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| 66 | assert.equal(true, eTest.iface(e));
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| 67 | assert.equal(true, eTest.iface(r.extend(f)));
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| 68 | assert.equal(true, eTest.iface(l.extend(f)));
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| 69 | });
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| 70 |
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| 71 | describe('#bimap', function() {
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| 72 |
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| 73 | it('maps the first function over the left value', function() {
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| 74 | var e = Either(1, null);
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| 75 | var result = e.bimap(add(1));
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| 76 | assert.equal(true, result.equals(Either(2, null)));
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| 77 | });
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| 78 |
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| 79 | it('maps the second function over the right value', function() {
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| 80 | var e = Either(null, 1);
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| 81 | var result = e.bimap(null, add(1));
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| 82 | assert.equal(true, result.equals(Either(null, 2)));
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| 83 | });
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| 84 |
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| 85 | });
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| 86 |
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| 87 | describe('#toString', function() {
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| 88 |
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| 89 | it('returns the string representation of a Left', function() {
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| 90 | assert.strictEqual(Either.Left('Cannot divide by zero').toString(),
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| 91 | 'Either.Left("Cannot divide by zero")');
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| 92 | });
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| 93 |
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| 94 | it('returns the string representation of a Right', function() {
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| 95 | assert.strictEqual(Either.Right([1, 2, 3]).toString(),
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| 96 | 'Either.Right([1, 2, 3])');
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| 97 | });
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| 98 |
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| 99 | });
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| 100 |
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| 101 | });
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