content: add extra test to drawing squares practice in lesson 6

close #486

Author: NathanLovato

course/lesson-6-multiple-function-parameters/drawing_squares/TestsDrawingSquares.gd

@@ -18,6 +18,19 @@ func _prepare():
 
 
 func test_turtle_ends_facing_towards_the_right() -> String:
+	var turn_right_between_jumps := 0
+	for command in turtle.get_command_stack():
+		if command.command == "turn":
+			turn_right_between_jumps += 1
+			if not is_equal_approx(command.angle, 90.0):
+				return tr("The turtle should always turn by 90 degrees. Instead, we found that it turned by %s degrees in one call to turn_right()." % command.angle)
+		elif command.command == "jump":
+			if turn_right_between_jumps != 4:
+				return tr("The turtle should turn four times to draw a square so that it always starts drawing the squares in the same direction. Did you call turn_right() four times?")
+	return ""
+
+
+func test_turtle_starts_each_square_facing_towards_the_right() -> String:
 	if not is_equal_approx(wrapf(turtle.turn_degrees, 0.0, 360.0), 0.0):
 		return tr(
 			"The turtle should be facing towards the right to draw squares in the same direction every time. Did you call turn_right(90) four times in your function?"

course/lesson-6-multiple-function-parameters/lesson.tres

@@ -338,7 +338,9 @@ We could use these squares as outlines when selecting units in a tactical game,
 
 Create a function named [code]draw_square()[/code] that takes one parameter: the [code]length[/code] of the square's sides.
 
-The turtle should face towards the right when starting or completing a rectangle."
+[b]The turtle should face towards the right when starting or completing a square.[/b]
+
+Be sure to call [b]turn_right(90)[/b]  enough times in your function to do so."
 starting_code = ""
 cursor_line = 0
 cursor_column = 0
@@ -357,7 +359,7 @@ goal = "Let's make our square drawing function more flexible to include rectangl
 
 Your job is to code a function named [code]draw_rectangle()[/code] that takes two parameters: the [code]length[/code] and the [code]height[/code] of the rectangle.
 
-The turtle should face towards the right when starting or completing a rectangle.
+[b]The turtle should face towards the right when starting or completing a rectangle.[/b]
 
 Note that we could still draw a square with [code]draw_rectangle()[/code] by having the [code]length[/code] and [code]height[/code] equal the same value."
 starting_code = "func draw_rectangle():

game_demos/DrawingTurtle.gd

@@ -207,15 +207,6 @@ func play_draw_animation() -> void:
 		line.start()
 
 
-# Animates the turtle's height and shadow scale when jumping. Tween the progress
-# value from 0 to 1.
-func _animate_jump(progress: float) -> void:
-	var parabola := -pow(2.0 * progress - 1.0, 2.0) + 1.0
-	_sprite.position.y = -parabola * 100.0
-	var shadow_scale := (1.0 - parabola + 1.0) / 2.0
-	_shadow.scale = shadow_scale * Vector2.ONE
-
-
 # Returns the total bounding rectangle enclosing all the turtle's drawn
 # polygons.
 func get_rect() -> Rect2:
@@ -227,6 +218,19 @@ func get_rect() -> Rect2:
 	return bounds
 
 
+func get_command_stack() -> Array:
+	return _command_stack.duplicate()
+
+
+# Animates the turtle's height and shadow scale when jumping. Tween the progress
+# value from 0 to 1.
+func _animate_jump(progress: float) -> void:
+	var parabola := -pow(2.0 * progress - 1.0, 2.0) + 1.0
+	_sprite.position.y = -parabola * 100.0
+	var shadow_scale := (1.0 - parabola + 1.0) / 2.0
+	_shadow.scale = shadow_scale * Vector2.ONE
+
+
 func _close_polygon() -> void:
 	if _points.empty():
 		return