Make automated regression tests for each supported reader and writer

[hinerm]

I severely broke writing with the N-D conversion in 0.7.0, and didn't catch it. It is too much of a burden to manually test the combinations of reading, writing and translation, but these are critical things to have test coverage over.

So we need to establish a pixel-based test like the test-images-good tests in Bio-Formats, and I don't think we should release 0.8.0 without it.

[hinerm]

• first pass test:
• create a variety of fakes
• Write them using each writer
• read them back with each reader
• port the Bio-Formats test-suite component to scifio, make maven run on every compile against fakes

[hinerm]

the comprehensive tests will be running the test suite against a scifio-compatible subset of test-images-good

[hinerm]

So we need to establish a pixel-based test like the test-images-good tests in Bio-Formats, and I
don't think we should release 0.8.0 without it.

Just kidding, this should be a priority for the remainder of 0.9.0. With a variety of breaking structural changes (e.g. SCIFIOConfig, restructuring to remove protected fields, writer initialization restructuring) it would be nice to have some peace of mind that significant parts of the framework are not being hosed, without resorting to manual testing.

[hinerm]

Should focus on porting the bio-formats testing framework. Also, it would be good to make these tests publicly reproducible by providing either a new repo or using git-annex to make at least 1 dataset for each supported format available.

[hinerm]

After discussion with @dietzc it seems like we should be able to do this easily with KNIME. Hooray!

[ctrueden]

Here is the current plan, as discussed on Gitter:

• @ctrueden Create samples.scif.io to host ZIP files of all sample data we are able to license under CC0.
• @ctrueden Update scif.io main website to have a "Sample Data" section, initially populated from the LOCI sample datasets, linking to samples.scif.io.
• @gab1one Make a list of still-needed samples for good test coverage. This will not be a full "SCIFIO supported formats" table.
• @gab1one Implement base logic in src/test/java for downloading and unpacking requested ZIPs from samples.scif.io, similar to this logic, and then reading the unpacked file(s), validating against known expected pixels & metadata values. (Consider the DRYest way to achieve this validation thoroughly. For metadata, my idea is to externalize the metadata using SCIFIO, and keep it along side the ZIPs, then verify that reparsed metadata matches the externalized information.)
• @gab1one Use the base logic in each format's regression tests to validate reading of real files.
• @ctrueden Once all is working, delete https://github.com/scifio/scifio-testing since it will no longer be necessary as a separate repository. Each repository's Format plugins should have corresponding tests leveraging the framework described above.