Issue 594: Property-Based Testing for Image Resizing and Preprocessing

[knoxiboy]

What does this PR do?

This PR implements property-based testing using Hypothesis for the preprocess_image_for_resnet function to verify that it correctly resizes and formats arbitrary image dimensions to the target shape.

Related Issue

Closes #594

Changes made

• Created property-based unit tests using the hypothesis package in tests/test_image_preprocessing.py.
• Added test_preprocess_image_for_resnet_property to test resizing behavior with various height/width dimensions for RGB images.
• Added test_preprocess_image_for_resnet_grayscale to test resizing behavior for grayscale (2D) images.
• Updated preprocess_image_for_resnet in app.py to handle grayscale (2D and 1-channel 3D) arrays gracefully by expanding them to 3 channels to comply with ResNet requirements.
• Addressed code review feedback:
  • Reduced generated image dimension strategy bounds to 500x500 to keep the CI pipeline quick and reliable.
  • Replaced constant-color comment descriptors to match actual generation strategies.
  • Allowed Hypothesis exceptions to propagate naturally instead of wrapping them in general try-except blocks.
  • Asserted a consistent 3-channel shape (1, 3, 224, 224) for grayscale test preprocessing results.

Checklist

• I have tested my changes
• My code follows project guidelines
• No new errors introduced

[github-actions]

Thanks for creating a PR for your Issue! ☺️

We'll review it as soon as possible.
In the meantime, please double-check the file changes and ensure that all commits are accurate.

If there are any unresolved review comments, feel free to resolve them. 🙌🏼

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds property-based tests for preprocess_image_for_resnet and introduces Hypothesis as a test dependency.

Changes:

• Added Hypothesis-driven tests to validate output tensor shapes for RGB and grayscale inputs.
• Added hypothesis to requirements.txt (and normalized the pytest-cov line formatting).

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 7 comments.

File	Description
tests/test_image_preprocessing.py	Adds property tests for image preprocessing output shapes across varying input sizes.
requirements.txt	Adds Hypothesis as a testing dependency.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[neeru24]

@knoxiboy resolve conflicts

[knoxiboy]

@knoxiboy resolve conflicts

Done