✅ Tests: Added DeFFcode unit tests with pytest. (Fixes #3)

[abhiTronix]

Brief Description

This PR implements complete pytest unit tests for DeFFcode APIs.

Requirements / Checklist

• [x] I have read the DeFFcode PR Guidelines.
• [x] I have read the DeFFcode Documentation.
• [x] I have updated the documentation files accordingly(if required).

Related Issue

3

Context

This PR brings complete pytest unit tests for DeFFcode APIs for comprehensively testing their stable working under different environments, and quickly discovering any anomalies if present in the respective code. This PR also imports bash scripts and useful functions from vidgear necessary for unit test working.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)