Fix tests for higher density screens.

test/bitmap.js

@@ -33,7 +33,9 @@ test('Get a bitmap of a specific size.', function(t)
 	var size = 10;
 	t.plan(2);
 	var img = robot.screen.capture(0, 0, size, size);
-
+
+	// Support for higher density screens.
+	if (img.width == (size*2)) size = img.width;
 	t.equals(img.height, size, 'make sure image is expected height.');
 	t.equals(img.width, size, 'make sure image is expected width.');
 });
@@ -47,25 +49,30 @@ test('Get a bitmap and make sure the colorAt works as expected.', function(t)
 	t.ok(/^[0-9A-F]{6}$/i.test(hex), "colorAt returned valid hex.");
 
 	var screenSize = robot.getScreenSize();
-
+	var width = screenSize.width;
+	var height = screenSize.height;
+
+	// Support for higher density screens.
+	if (img.width === (width*2)) width = img.width; height = img.height;
+
 	t.throws(function()
 	{
-		img.colorAt(0, screenSize.height);
+		img.colorAt(0, height);
 	}, /are outside the bitmap/, 'colorAt (0, screen.height) threw an error.');
 
 	t.doesNotThrow(function()
 	{
-		img.colorAt(0, screenSize.height-1);
+		img.colorAt(0, height-1);
 	}, /are outside the bitmap/, 'colorAt (0, screen.height-1) did not throw an error.');
 
 	t.throws(function()
 	{
-		img.colorAt(screenSize.width, 0);
+		img.colorAt(width, 0);
 	}, /are outside the bitmap/, 'colorAt (screen.width, 0) threw an error.');
 
 	t.doesNotThrow(function()
 	{
-		img.colorAt(screenSize.width-1, 0);
+		img.colorAt(width-1, 0);
 	}, /are outside the bitmap/, 'colorAt (screen.width-1, 0) did not throw an error.');
 
 	t.throws(function()