Lesson 11 Time Delta: Rotating Using Delta Practice BUG

[DonVonDolo]

When I went to multiply delta to the rotate(2) I left it outside the parenthesis but it still said I was doing it right and congratulated me and sent me on my way to the next practice where I did the same mistake and I was wrong. I didn't realize until I showed a friend who went through the course and he said that should not have said I was right.

To Reproduce
Steps to reproduce the bug:

1. Go to https://gdquest.github.io/learn-gdscript/#course/lesson-11-time-delta/lesson.tres
2. Click on Rotating Using Delta Practice
3. put in the code:
   func process(delta):
   rotate(2) * delta

Expected behavior
Although I did not know at the time, it is supposed to tell me I was wrong and put the * delta inside the parenthesis next to the 2

Information about your device (please complete the following information):

• Operating System: Windows 10
• Browser: Firefox

[phealy3330]

This also happens with the Linux version of the learn to code app
https://user-images.githubusercontent.com/13488079/196044851-50df31bc-8d04-4a70-883d-9f489644750c.mov

I think possibly the bug is in the test_rotating_character_is_time_dependent() function

learn-gdscript/course/lesson-11-time-delta/rotating-using-delta/TestsRotatingDelta.gd

Line 23 in 11730a3

func test_rotating_character_is_time_dependent() -> String:

It looks like the check logic does this:
var has_delta: bool = _body.rfind("delta") > 0
Does the body of the code have the string delta? Which passes

var is_in_parentheses: bool = _body.rfind(")")
Does the body of the code have a close-parenthesis? Which also passes

The second check seems to pass for similar reasons:

learn-gdscript/course/lesson-11-time-delta/rotating-using-delta/TestsRotatingDelta.gd

Line 35 in 11730a3

func test_rotation_speed_is_2_radians_per_second() -> String:

In test_rotation_speed_is_2_radians_per_second()

		var has_multiplication_sign: bool = _body.rfind("*") > 0
		var has_two: bool = _body.rfind("2") > 0 and not _body.rfind(".2") > 0

The code also has a multiplication sign and a 2.

Maybe these two checks can be combined into a single string to search for, something like this super ugly regex:
grep -Ei "(\(\s*2\s*\*\s*delta\s*\))|(\(\s*delta\s*\*\s*2\s*\))"
( [any whitepsace] delta [any whitespace] * [any whitespace] 2 [any whitespace]) OR ( [any whitepsace] 2 [any whitespace] * [any whitespace] delta [any whitespace])

[phealy3330]

Digging in a little more I see that the code is doing basically that check in the happy path by removing all whitespace

learn-gdscript/course/lesson-11-time-delta/rotating-using-delta/TestsRotatingDelta.gd

Line 20 in 11730a3

_has_proper_body = _body.replace(" ", "") in ["rotate(delta*2)", "rotate(2*delta)"]

But, seems like if it doesn't have the proper body it moves on to the individual checks, but if all the individual checks pass them lesson is marked as success. I cloned the repo and added in this check, seems to work ok to catch the false successes- hope this is useful

func test_regex_passes_checks() -> String:
	var regex = RegEx.new()
	regex.compile("(\\(\\s*2\\s*\\*\\s*delta\\s*\\))|(\\(\\s*delta\\s*\\*\\s*2\\s*\\))")
	var result = regex.search(_body)
	if result:
		print("REGEX hit: %s " % result.get_string()) # Would print n-0123
		return ""
	else:
		print("REGEX fail")
		return("Regex failed")

learn-gdscript-app-2022-10-16_14.43.03.mp4

[phealy3330]

Working on a PR for this

[NathanLovato]

Thanks much! :)