Added player test start. Took me forever to find out that I have to s…

…et a non 0,0 Player position in order to have it actually receive the input events. This is not documented in the GUT docs and I might create a PR to add it.

test/unit/test_player.gd

@@ -0,0 +1,20 @@
+extends GutTest
+
+var Player: PackedScene = load('res://player.tscn')
+
+var _sender = InputSender.new()
+
+func after_each():
+	_sender.release_all()
+	_sender.clear()
+
+func test_move_right_adds_positive_x_velocity():
+	var player = add_child_autofree(Player.instantiate())
+	# todo: find out why it only works when setting the position here, 0,0 does not work
+	player.position = Vector2(1, 1)
+
+	_sender.action_down("move_right").wait_frames(1)
+	await(_sender.idle)
+
+	assert_gt(player.position.x, 0.0, "Player should move right")
+