add tests for usage and listing devices

test/cli.tests.js

@@ -0,0 +1,56 @@
+'use strict';
+
+const sinon = require('sinon');
+const assert = require('assert');
+const proxyquire = require('proxyquire');
+
+describe('cli', () => {
+    let sandbox;
+    let consoleLogSpy;
+
+    beforeEach(() => {
+        sandbox = sinon.sandbox.create();
+        consoleLogSpy = sandbox.spy(console, 'log');
+    });
+
+    afterEach(function() {
+        sandbox.restore();
+    });
+
+    it('shows help', function() {
+        const minimistStub = sandbox.stub();
+        minimistStub.returns({h: true});
+
+        const cli = proxyquire('../cli.js', {
+            'minimist': minimistStub,
+            './usage.js': '[usage]'
+        });
+        assert.equal(consoleLogSpy.callCount, 1);
+        assert.equal(consoleLogSpy.args[0][0], '[usage]');
+    });
+
+    it('lists devices', function() {
+        const minimistStub = sandbox.stub();
+        minimistStub.returns({l: true});
+        const getDevicesStub = sandbox.stub();
+        getDevicesStub.returns({
+            then: cb => cb({
+                LVDS1: {connected: true},
+                HDMI2: {connected: false}
+            })
+        });
+
+        const cli = proxyquire('../cli.js', {
+            'minimist': minimistStub,
+            './swm.js': {
+                getDevices: getDevicesStub
+            }
+        });
+        assert.equal(getDevicesStub.callCount, 1);
+        assert.equal(consoleLogSpy.callCount, 3);
+        assert.equal(consoleLogSpy.args[0][0], 'Detected devices:\n');
+        assert.equal(consoleLogSpy.args[1].join(' '), 'LVDS1: Connected');
+        assert.equal(consoleLogSpy.args[2].join(' '), 'HDMI2: Disconnected');
+    });
+});
+