Improve Instagram App Test Coverage

[Copilot]

Description

This pull request adds comprehensive unit tests for the admin actions, models, serializers, and signal handlers in the Instagram app. The new tests focus on verifying custom admin actions, model behaviors, serializer validation and creation logic, and signal-triggered background tasks, improving the reliability and coverage of critical features.

Admin actions testing:

• Adds tests for custom admin actions in InstagramUserAdmin, verifying correct behavior and error handling for updating user profiles and queuing story/post updates via API. (instagram/tests/admin/test_user_admin.py)

Model logic testing:

• Adds tests for StoryCredit and StoryCreditPayment models, including string representations, credit accumulation, and ensuring credits are created and updated correctly when payments are made. (instagram/tests/models/test_credit.py)

Serializer validation and creation:

• Adds tests for user creation and history serializers, covering username validation, profile picture logic, and story credit validation, including edge cases for negative and zero values. (instagram/tests/serializers/test_serializers.py)

Signal handler testing:

• Adds tests for Django signal handlers for user, story, post, and post media models, verifying that background tasks are correctly queued or skipped based on model field values and ensuring media downloads and post-processing are triggered as expected. (instagram/tests/signals/test_signals.py)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!