Merge pull request #130 from t-bonatti/emit-events

 Emit events on finished task / Execute function or promise

src/task.js

@@ -5,17 +5,28 @@ const EventEmitter = require('events');
 class Task extends EventEmitter{
     constructor(execution){
         super();
-        if(typeof execution !== 'function'){
+        if(typeof execution !== 'function') {
             throw 'execution must be a function';
         }
+        this._execution = execution;
+    }
 
-        this.execute = (now) => {
-            // TODO: Handle execution
-            // check if execution returns a promise
-            // emit events on start and on finished
-            // force execution return a promise
-            return execution(now);
-        };
+    execute(now) {
+        let exec;
+        try {
+            exec = this._execution(now);
+        } catch (error) {
+            return this.emit('task-failed', error);
+        }
+
+        if (exec instanceof Promise) {
+            return exec
+                .then(() => this.emit('task-finished'))
+                .catch((error) => this.emit('task-failed', error));
+        } else {
+            this.emit('task-finished');
+            return exec;
+        }
     }
 }
 

test/task-test.js

@@ -0,0 +1,49 @@
+const { assert } = require('chai');
+const sinon = require('sinon');
+const Task = require('../src/task');
+
+describe('Task', () => {
+    beforeEach(() => {
+        this.clock = sinon.useFakeTimers(new Date(2018, 0, 1, 0, 0, 0, 0));
+    });
+
+    afterEach(() => {
+        this.clock.restore();
+    });
+
+    it('should emit event on finish a task', async () => {
+        let finished = false;
+        let task = new Task(() => 'ok');
+        task.on('task-finished', () => finished = true);
+        await task.execute();
+        assert.equal(true, finished);
+    });
+
+    it('should emit event on error a task', async () => {
+        let error;
+        let task = new Task(() => {
+            throw Error('execution error');
+        });
+        task.on('task-failed', (err) => error = err.message);
+        await task.execute();
+        assert.equal('execution error', error);
+    });
+
+    it('should emit event on finish a promise task', async () => {
+        let finished = false;
+        const promise = () => new Promise((resolve) => resolve('ok'));
+        let task = new Task(promise);
+        task.on('task-finished', () => finished = true);
+        await task.execute();
+        assert.equal(true, finished);
+    });
+
+    it('should emit event on error a promise task', async () => {
+        let failed = false;
+        const promise = () => new Promise((resolve, reject) => reject('errou'));
+        const task = new Task(promise);
+        task.on('task-failed', (error) => failed = error);
+        await task.execute();
+        assert.equal('errou', failed);
+    });
+});