# Test Plan for `ColorFeaturesPyramid`

## Overview
This document outlines the plan for testing and documenting the `ColorFeaturesPyramid` class.

## 1. Understanding the `ColorFeaturesPyramid` Class
- The `ColorFeaturesPyramid` class performs pyramid down-sampling and color feature analysis on images.
- It relies on the `ColorFeaturesTile` class for tile-based analysis.
- Key parameters:
  - `uuid`: Identifier for the image.
  - `tilew` and `tileh`: Dimensions of the tiles for analysis.
  - `down_sampling`: Number of down-sampling levels.
  - `colorspace`: Color space for analysis (e.g., `lab`, `rgb`, `hsv`).
- The class reads an image, down-samples it, and analyzes the tiles at each level.

## 2. Design the Test Function
### Test Scope
Unit tests to verify the functionality of the `ColorFeaturesPyramid` class.

### Test Cases
1. **Initialization Test**:
   - Verify that the class initializes correctly with default and custom parameters.
   - Ensure that the `check_params` function from `utils.py` is used correctly.
2. **Down-Sampling Test**:
   - Verify that the down-sampling process works as expected.
   - Check that the down-sampled images are saved correctly.
3. **Tile Analysis Test**:
   - Verify that the tile analysis produces the expected output.
   - Ensure that the histograms are computed correctly.
4. **Edge Cases**:
   - Test with invalid inputs (e.g., non-existent image, invalid color space).
   - Test with extreme values for parameters (e.g., very large or small tile sizes).

### Testing Framework
Use `pytest` for writing and running the tests.

## 3. Document the Test Function
- Write clear docstrings for the test function.
- Include examples of how to use the `ColorFeaturesPyramid` class.
- Document the expected behavior and assumptions.
- Add comments to explain the purpose of each test case.

## 4. Plan the Implementation
- Create a new test file: `test_color_features_pyramid.py`.
- Implement the test function and test cases.
- Ensure the test function is modular and reusable.
- Use the `check_params` function from `utils.py` to validate parameters.

## 5. Verify the Plan
- Review the plan to ensure all aspects are covered.
- Confirm that the test function aligns with the purpose of the `ColorFeaturesPyramid` class.