Task results and status in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Django test client.

Django

from django.test import [1]

Drag options to blanks, or click blank then click option'

AClient

BRequestFactory

CTestCase

DSimpleTestCase

Attempts:

3 left

💡 Hint

Common Mistakes

Importing TestCase instead of Client

Using RequestFactory which is different

Forgetting to import anything

The Django test client is imported using Client from django.test. It allows simulating user requests in tests.

2fill in blank

medium

Complete the code to check if a test response status code is 200 (OK).

Django

self.assertEqual(response.[1], 200)

Drag options to blanks, or click blank then click option'

Astatus_code

Bstatus

Ccode

Dhttp_status

Attempts:

3 left

💡 Hint

Common Mistakes

Using response.status instead of response.status_code

Using response.code which does not exist

The response object in Django tests has a status_code attribute that holds the HTTP status code returned.

3fill in blank

hard

Fix the error in the test method to correctly check for a redirect status.

Django

self.assertEqual(response.[1], 302)

Drag options to blanks, or click blank then click option'

Aredirect_code

Bstatus

Cstatus_code

Dhttp_redirect

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent attributes like redirect_code

Using status instead of status_code

The correct attribute to check the HTTP status code, including redirects, is status_code.

4fill in blank

hard

Fill both blanks to assert the response contains the text 'Welcome' and has status 200.

Django

self.assertContains(response, [1])
self.assertEqual(response.[2], 200)

Drag options to blanks, or click blank then click option'

A'Welcome'

Bstatus_code

Cstatus

D'Hello'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute for status code

Using wrong text string in assertContains

assertContains checks if the response content includes the given text. The status code is checked with status_code.

5fill in blank

hard

Fill all three blanks to check the response is a redirect to '/login/' with status 302.

Django

self.assertEqual(response.[1], 302)
self.assertEqual(response.[2], '/login/')
self.assertTrue(response.[3])

Drag options to blanks, or click blank then click option'

Astatus_code

Burl

Chas_header('Location')

Dredirect_url

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute names for URL or status

Not checking for the 'Location' header

The status code for redirect is checked with status_code. The redirect target URL is in url. The presence of the 'Location' header is checked with has_header('Location').

Practice

1. In Django with Celery, which object do you use to check the status and result of a background task by its ID?

easy

A. AsyncResult

B. TaskStatus

C. TaskResult

D. ResultChecker

Solution

1. Step 1: Identify the object for task tracking

   Celery provides AsyncResult to track task status and results using the task ID.

2. Step 2: Confirm usage in Django context

   In Django projects using Celery, AsyncResult is the standard way to check if a task is pending, running, or finished.

3. Final Answer:

   AsyncResult -> Option A

4. Quick Check:

   Task status and results = AsyncResult [OK]

Hint: Remember: AsyncResult tracks task status by ID [OK]

Common Mistakes:

• Confusing AsyncResult with task function names
• Using non-existent classes like TaskStatus
• Trying to access results directly without AsyncResult

2. Which of the following is the correct way to create an AsyncResult instance for a task with ID stored in task_id?

easy

A. result = AsyncResult(task=task_id)

B. result = AsyncResult.get(task_id)

C. result = AsyncResult.fetch(task_id)

D. result = AsyncResult(task_id)

Solution

1. Step 1: Recall AsyncResult constructor usage

   The AsyncResult class is instantiated by passing the task ID as the first argument.

2. Step 2: Check each option's syntax

   Only AsyncResult(task_id) correctly creates the instance. Methods like .get() or .fetch() are not constructors.

3. Final Answer:

   result = AsyncResult(task_id) -> Option D

4. Quick Check:

   Instantiate AsyncResult with task ID directly [OK]

Hint: Use AsyncResult(task_id) to create result object [OK]

Common Mistakes:

• Calling get() or fetch() as constructor
• Passing keyword argument 'task' instead of positional
• Confusing AsyncResult with task function calls

3. Given the code:

result = AsyncResult('abc123')
status = result.status
output = result.result

What will status and output represent if the task is still running?

medium

A. status is 'PENDING', output is None

B. status is 'RUNNING', output is None

C. status is 'FAILURE', output is the error info

D. status is 'SUCCESS', output is the task result

Solution

1. Step 1: Understand AsyncResult status values

   By default, while a task is running without calling update_state inside the task, result.status remains 'PENDING'.

2. Step 2: Check result property during running

   result.result returns None until the task completes.

3. Final Answer:

   status is 'PENDING', output is None -> Option A

4. Quick Check:

   Running task (default): status='PENDING', result=None [OK]

Hint: Default running tasks show status 'PENDING' and result None [OK]

Common Mistakes:

• Mistaking for 'RUNNING' status (doesn't exist)
• Confusing with 'STARTED' which requires explicit update_state
• Thinking result is available before completion

4. You wrote:

result = AsyncResult(task_id)
if result.status == 'SUCCESS':
    print(result.result)
else:
    print('Task not done')

But it always prints 'Task not done' even after task completion. What is the likely issue?

medium

A. You must call result.get() instead of accessing result.result

B. You should check for 'COMPLETED' instead of 'SUCCESS'

C. The task ID is incorrect or expired

D. AsyncResult does not have a status attribute

Solution

1. Step 1: Understand status checking logic

   The code checks if result.status equals 'SUCCESS' to print the result.

2. Step 2: Identify why status never shows 'SUCCESS'

   If the task ID is wrong or expired, AsyncResult will not find the task and status stays 'PENDING' or similar.

3. Final Answer:

   The task ID is incorrect or expired -> Option C

4. Quick Check:

   Wrong task ID causes status never to be 'SUCCESS' [OK]

Hint: Check task ID validity if status never changes [OK]

Common Mistakes:

• Using wrong status string like 'COMPLETED'
• Assuming result.result always updates without completion
• Ignoring task ID correctness

5. You want to handle a task result in Django only if it succeeded, otherwise log the error. Which code snippet correctly checks the task status and safely accesses the result or error?

hard

A. result = AsyncResult(task_id)
if result.ready():
handle(result.result)
else:
log_error('Task not ready')

B. result = AsyncResult(task_id)
try:
handle(result.get(timeout=1))
except Exception as e:
log_error(e)

C. result = AsyncResult(task_id)
if result.status == 'PENDING':
handle(result.result)
else:
log_error('Task failed')

D. result = AsyncResult(task_id)
if result.status == 'SUCCESS':
handle(result.result)
elif result.status == 'FAILURE':
log_error(result.get())

Solution

1. Step 1: Understand safe result retrieval

   Using result.get() with a timeout waits for completion and raises exceptions on failure.

2. Step 2: Check error handling approach

   Wrapping result.get() in try-except catches task failures and allows logging errors safely.

3. Step 3: Compare other options

   Options B, C, and D do not handle exceptions properly; C incorrectly treats 'PENDING' as success.

4. Final Answer:

   Use try-except with result.get() to handle success and failure -> Option B

5. Quick Check:

   Use result.get() with try-except for safe task result handling [OK]

Hint: Use try-except with result.get() to catch errors [OK]

Common Mistakes:

• Checking only status strings without exception handling
• Assuming ready() means success
• Treating PENDING as success