AddingATest.md

Adding a new test to the repo

This walkthrough takes one through steps it takes to add a simple test to the library.

1. Add image/images to test-images

test-images directory is the repo that contains sample images that help test for regressions and correctness.

It contains a set of small/medium-sized images that stress certain parts of the decoder, so in case we have a regression we don't want to occur, we add the image to test-images.

The structure is test-images->format->[images] for ease of use.

• Remember to add the images to VCS

2. Add the file details to tests/tests/[{format}.json]

E.g there is a jpeg.json which contains information about jpeg files.

The format is simple

Field	Status	Explanation
name	Mandatory	File name with extension
hash	Mandatory	xxhash(seed of 0) result of the decoded result still not in planar format
colorspace	Optional	Expected colorspace output of the image, only used by zune-jpeg currently
comment	Optional	A reason why the file exists, useful for debugging purposes

Here is an example of such a file description

{
  "name": "weid_sampling_factors.jpg",
  "hash": 290923794124024565485763288568005295883,
  "comment": "Non normal sampling factors, h2v1 for all components",
  "colorspace": "rgb"
}

Each entry is part of an array, so it should be inside []

Tip: Incase you don't know the hash and you have ensured the output is correct(matches other libraries)

• Run the testing once, once you get the error, copy the hash printed to stdout

3. Run decoder

Ensure nothing is failing.

4. Profit.

Now we can easily track regressions