Change test dir structure

[jitsedesmet]

This pull request aims to close #34 . Following tasks where already done:

• Testing between operators is inconsistent
• Util folder needs documentation and cleanup

This PR just handles the last task:

• Util.test needs to be renamed

It does this by changing the structure, the discussion for this structure can be found in #34 .

[coveralls]

Pull Request Test Coverage Report for Build 1123171771

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 88.294%

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Totals
Change from base Build 1122187400:	0.0%
Covered Lines:	1298
Relevant Lines:	1430

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💛 - Coveralls