For ticket "Create/Update Comments" course software bug with proof

MongoDB University M220P: MongoDB for Python Developers
#1

For ticket “Create/Update Comments” the unit test and the run.py application pass different data types to update_comment. For parameter comment_id the unit test passes an object ID but the run.py application passes a hex string. Therefore the unit test and the application can never both pass. Below is the dbg output for both cases verifying this course software bug.

  1. Using the Unit Test

(mflix) C:\test\mongodb\m220p>pytest -m create_update_comments
============================= test session starts =============================
platform win32 – Python 3.6.10, pytest-3.3.0, py-1.8.0, pluggy-0.6.0
rootdir: C:\test\mongodb\m220p, inifile: pytest.ini
plugins: flask-0.11.0
collected 43 items

tests\test_create_update_comments.py .

PDB set_trace (IO-capturing turned off) >>>>>>>>>>>>>>>>>>>
c:\test\mongodb\m220p\mflix\db.py(377)update_comment()
-> response = db.comments.update_one(
(Pdb) l
372 “”"
373 # TODO: Create/Update Comments
374 # Use the user_email and comment_id to select the proper comment, then
375 # update the “text” and “date” of the selected comment.
376 import pdb; pdb.set_trace()
377 -> response = db.comments.update_one(
378 { “_id”: comment_id, “email”: user_email },
379 { “$set”: { “text”: text, “date”: date } }
380 )
381
382 return response
(Pdb) p comment_id
ObjectId(‘5f3a20de7526b648a4d9e7ce’)

…
(Pdb) c
… [100%]

============================= 39 tests deselected =============================
================== 4 passed, 39 deselected in 146.88 seconds ==================

  1. Running the main application

(mflix) C:\test\mongodb\m220p>python run.py

  • Restarting with stat
  • Debugger is active!
  • Debugger PIN: 166-656-048
  • Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
    127.0.0.1 - - [17/Aug/2020 02:20:48] “GET / HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:48] “GET /static/css/main.2637239d.chunk.css HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:48] “GET /static/js/main.de4ec786.chunk.js HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:50] “GET /api/v1/movies/ HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:51] “GET /api/v1/movies/facet-search?cast=Denzel%20Washington&page=0 HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:51] “GET /api/v1/movies/facet-search?cast=Morgan%20Freeman&page=2 HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:20:52] “GET /static/media/pixelatedLeaf.6c93bd20.svg HTTP/1.1” 200 -
    127.0.0.1 - - [17/Aug/2020 02:21:01] “POST /api/v1/user/register HTTP/1.1” 201 -
    127.0.0.1 - - [17/Aug/2020 02:21:02] “POST /api/v1/user/register HTTP/1.1” 201 -
    127.0.0.1 - - [17/Aug/2020 02:21:02] “POST /api/v1/movies/comment HTTP/1.1” 200 -

c:\test\mongodb\m220p\mflix\db.py(377)update_comment()
-> response = db.comments.update_one(
(Pdb) l
372 “”"
373 # TODO: Create/Update Comments
374 # Use the user_email and comment_id to select the proper comment, then
375 # update the “text” and “date” of the selected comment.
376 import pdb; pdb.set_trace()
377 -> response = db.comments.update_one(
378 { “_id”: comment_id, “email”: user_email },
379 { “$set”: { “text”: text, “date”: date } }
380 )
381
382 return response
(Pdb) p comment_id
‘5f3a21ce7526b64b3c3daf9f’
(Pdb) c
127.0.0.1 - - [17/Aug/2020 02:21:29] “PUT /api/v1/movies/comment HTTP/1.1” 400 -
c:\test\mongodb\m220p\mflix\db.py(377)update_comment()
-> response = db.comments.update_one(
(Pdb) p comment_id
‘5f3a21ce7526b64b3c3daf9f’
(Pdb) c
127.0.0.1 - - [17/Aug/2020 02:21:38] “PUT /api/v1/movies/comment HTTP/1.1” 400 -

#2

Thanks for your feedback. I will check this out. :slight_smile:

Kanika

#3

It would appear you’re not wrapping comment_id in ObjectId() in the filter. Or am I missing something?

1 Like
#4

You’re missing something. The unit test is passing that argument as an object id. The application is passing that same argument as a string. For the unit test case you can’t wrap something that is already an object id as an object id. Incidentally I got it to work for both cases with:

if type(comment_id) == str:
    comment_id = ObjectId(comment_id)

But it is a course material bug that’s creating difficulty for many as you can see from this forum.

#5

Thanks @David_18019 for pointing this out. We would surely check this in our course material and fix it. :slight_smile:

Cc @Shubham_Ranjan

Kanika

#6

Thanks @David_18019 for surfacing this. We will look into it.

Thanks @kanikasingla !

~ Shubham