Improve the tests suite

[punkeel]

Unit tests should be improved

To be useful, the bleach would have to be split into smaller chunks (the PDF Bleach being ~500 lines is awful)

Integration/Functional/Whatever tests

Having a corpus of documents would be awesome, using olevba/pdfid/grep/file/zip to detect multiple points. The docs would need to be non sensitive/copyrighted documents.

• the file looks like it's a valid file (mime type, Office OOXML document contains a rels file, ...)
• No threats recognised by another tool are present
• Scan the file using VirusTotal?

I have started a corpus, and will work harder to have one file of each format and for each threat.