Fixes client up/down, left/right, front/back, clockwise/counterclockw…

…ise functions to accept 0 speed. Adds test. Resolves felixge#106

Previous implementation would not allow one to supply 0 for speed to stop moving along that axis. The only way to stop would be to issue a client.stop(). But that would also cancel any other movement going on at the time.
For example, centering a joystick should stop pitch, but should not stop yaw being controlled by a dpad on the same controller.

lib/Client.js

@@ -269,7 +269,7 @@ var pcmdOptions = [
 
 pcmdOptions.forEach(function(pair) {
   Client.prototype[pair[0]] = function(speed) {
-    if (!speed) {
+    if (isNaN(speed)) {
       return;
     }
     speed = parseFloat(speed);
@@ -281,7 +281,7 @@ pcmdOptions.forEach(function(pair) {
   };
 
   Client.prototype[pair[1]] = function(speed) {
-    if (!speed) {
+    if (isNaN(speed)) {
       return;
     }
 

test/unit/test-Client.js

@@ -322,6 +322,40 @@ test('Client', {
     assert.strictEqual(this.client._pcmd.down, -0.5);
   },
 
+  'pcmd methods accept 0 as speed': function() {
+    this.client.up(0);
+    assert.equal(this.client._pcmd.up, 0);
+    assert.equal(this.client._pcmd.down, undefined);
+
+    this.client.down(0);
+    assert.equal(this.client._pcmd.down, 0);
+    assert.equal(this.client._pcmd.up, undefined);
+
+    this.client.left(0);
+    assert.equal(this.client._pcmd.left, 0);
+    assert.equal(this.client._pcmd.right, undefined);
+
+    this.client.right(0);
+    assert.equal(this.client._pcmd.right, 0);
+    assert.equal(this.client._pcmd.left, undefined);
+
+    this.client.front(0);
+    assert.equal(this.client._pcmd.front, 0);
+    assert.equal(this.client._pcmd.back, undefined);
+
+    this.client.back(0);
+    assert.equal(this.client._pcmd.back, 0);
+    assert.equal(this.client._pcmd.front, undefined);
+
+    this.client.clockwise(0);
+    assert.equal(this.client._pcmd.clockwise, 0);
+    assert.equal(this.client._pcmd.counterClockwise, undefined);
+
+    this.client.counterClockwise(0);
+    assert.equal(this.client._pcmd.counterClockwise, 0);
+    assert.equal(this.client._pcmd.clockwise, undefined);
+  },
+
   'pcmd checks if argument exists': function() {
     // check that running without commands does not modify _pcmd state
     this.client.up(0.5);