1 files changed, 86 insertions, 0 deletions
diff --git a/mocha_test/compose.js b/mocha_test/compose.js
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+++ b/mocha_test/compose.js
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+var async = require('../lib/async');
+var expect = require('chai').expect;
+
+describe('compose', function(){
+    context('all functions succeed', function(){
+        it('yields the result of the composition of the functions', function(done){
+            var add2 = function (n, cb) {
+                setTimeout(function () {
+                    cb(null, n + 2);
+                });
+            };
+            var mul3 = function (n, cb) {
+                setTimeout(function () {
+                    cb(null, n * 3);
+                });
+            };
+            var add1 = function (n, cb) {
+                setTimeout(function () {
+                    cb(null, n + 1);
+                });
+            };
+            var add2mul3add1 = async.compose(add1, mul3, add2);
+            add2mul3add1(3, function (err, result) {
+                expect(err).to.not.exist;
+                expect(result).to.eql(16);
+                done();
+            });
+        });
+    });
+
+    context('a function errors', function(){
+        it('yields the error and does not call later functions', function(done){
+            var add1called = false;
+            var mul3error = new Error('mul3 error')
+            var add2 = function (n, cb) {
+                setTimeout(function () {
+                    cb(null, n + 2);
+                });
+            };
+            var mul3 = function (n, cb) {
+                setTimeout(function () {
+                    cb(mul3error);
+                });
+            };
+            var add1 = function (n, cb) {
+                add1called = true;
+                setTimeout(function () {
+                    cb(null, n + 1);
+                });
+            };
+            var add2mul3add1 = async.compose(add1, mul3, add2);
+            add2mul3add1(3, function (err, result) {
+                expect(err).to.eql(mul3error);
+                expect(result).to.not.exist;
+                expect(add1called).to.be.false;
+                done();
+            });
+        });
+    });
+
+    it('calls each function with the binding of the composed function', function(done){
+        var context = {};
+        var add2Context = null;
+        var mul3Context = null;
+        var add2 = function (n, cb) {
+            add2Context = this;
+            setTimeout(function () {
+                cb(null, n + 2);
+            });
+        };
+        var mul3 = function (n, cb) {
+            mul3Context = this;
+            setTimeout(function () {
+                cb(null, n * 3);
+            });
+        };
+        var add2mul3 = async.compose(mul3, add2);
+        add2mul3.call(context, 3, function (err, result) {
+            expect(err).to.not.exist;
+            expect(result).to.eql(15);
+            expect(add2Context).to.equal(context);
+            expect(mul3Context).to.equal(context);
+            done();
+        });
+    });
+});