Power usage node (#39)

* Add power usage node

* Add power usage node tests

* Register power usage node

package.json

@@ -32,7 +32,8 @@
       "ewelink-firmware-version": "src/firmware-version/firmware-version.js",
       "ewelink-power-state": "src/power-state/power-state.js",
       "ewelink-channel-count": "src/channel-count/channel-count.js",
-      "ewelink-event-listener": "src/event-listener/event-listener.js"
+      "ewelink-event-listener": "src/event-listener/event-listener.js",
+      "ewelink-power-usage": "src/power-usage/power-usage.js"
     }
   },
   "dependencies": {

src/power-usage/power-usage.html

@@ -0,0 +1,35 @@
+<script type="text/javascript">
+  RED.nodes.registerType('ewelink-power-usage', {
+    category: 'eWeLink',
+    color: '#a6bbcf',
+    defaults: {
+      name: { value: '' },
+      deviceId: { value: '' },
+      auth: { value: '', type: 'ewelink-credentials' }
+    },
+    inputs: 1,
+    outputs: 1,
+    label: function () {
+      return this.name || 'eWeLink Power Usage';
+    }
+});
+</script>
+
+<script type="text/x-red" data-template-name="ewelink-power-usage">
+  <div class="form-row">
+    <label for="node-input-name"><i class="icon-tag"></i> Name</label>
+    <input type="text" id="node-input-name" placeholder="Name">
+  </div>
+  <div class="form-row">
+    <label for="node-input-name"><i class="icon-tag"></i> Device ID</label>
+    <input type="text" id="node-input-deviceId" placeholder="Device ID">
+  </div>
+  <div class="form-row">
+    <label for="node-input-auth"><i class="icon-tag"></i> eWeLink Credentials</label>
+    <input type="text" id="node-input-auth" placeholder="eWeLink Credentials">
+  </div>
+</script>
+
+<script type="text/x-red" data-help-name="ewelink-power-usage">
+  <p>Retrieves or sets the power state of the device</p>
+</script>

src/power-usage/power-usage.js

@@ -0,0 +1,22 @@
+const eWeLinkConnect = require('../utils/ewelink-connect');
+
+/**
+ * Power usage node.
+ */
+module.exports = (RED) => {
+  /**
+   * Power usage node constructor.
+   * 
+   * @param {object} config The node configuration.
+   */
+  function PowerUsageNode(config) {
+    // Create the node
+    RED.nodes.createNode(this, config);
+
+    // Initialize device node
+    eWeLinkConnect.initializeDeviceNode(RED, this, config, 'getDevicePowerUsage');
+  }
+
+  // Register node
+  RED.nodes.registerType('ewelink-power-usage', PowerUsageNode);
+}

test/power-usage_spec.js

@@ -0,0 +1,74 @@
+const chai = require('chai');
+const expect = chai.expect;
+const sinon = require('sinon');
+const helper = require('node-red-node-test-helper');
+const credentialsNode = require('../src/credentials/credentials');
+const powerUsageNode = require('../src/power-usage/power-usage');
+const eWeLinkConnect = require('../src/utils/ewelink-connect');
+
+describe('Power Usage Node', () => {
+
+  beforeEach(done => {
+    helper.startServer(done);
+  });
+
+  afterEach(done => {
+    helper.unload().then(() => {
+      helper.stopServer(done);
+    });
+  });
+
+  it('should be loaded', done => {
+    const flow = [
+      { id: 'n1', type: 'ewelink-credentials' },
+      { id: 'n2', type: 'ewelink-power-usage', auth: 'n1', deviceId: '12345', name: 'Device 123' }
+    ];
+    helper.load([credentialsNode, powerUsageNode], flow, () => {
+      const n2 = helper.getNode('n2');
+
+      n2.should.have.property('name', 'Device 123');
+
+      done();
+    });
+  });
+
+  it('should return the result of the call', done => {
+    const connection = { getDevicePowerUsage() { } };
+
+    const methodStub = sinon.stub(connection, 'getDevicePowerUsage')
+      .callsFake(() => Promise.resolve({ methodResult: 'great' }));
+
+    const loginStub = sinon.stub(eWeLinkConnect, 'login')
+      .callsFake(() => Promise.resolve(connection));
+
+    const flow = [
+      { id: 'n1', type: 'ewelink-credentials' },
+      { id: 'n2', type: 'ewelink-power-usage', auth: 'n1', deviceId: '12345', wires: [['n4']] },
+      { id: 'n3', type: 'helper', wires: [['n2']] },
+      { id: 'n4', type: 'helper' }
+    ];
+    helper.load([credentialsNode, powerUsageNode], flow, () => {
+      const n2 = helper.getNode('n2');
+      const n3 = helper.getNode('n3');
+      const n4 = helper.getNode('n4');
+
+      setTimeout(() => {
+        n2.on('input', () => {
+          sinon.assert.calledWith(methodStub, '12345');
+          sinon.assert.calledOnce(loginStub);
+
+          methodStub.restore();
+          loginStub.restore();
+
+          n4.on('input', msg => {
+            expect(msg).to.deep.include({ payload: { methodResult: 'great' } });
+
+            done();
+          });
+        });
+
+        n3.send({ payload: '' });
+      });
+    });
+  });
+});