Increase test coverage

[fmigneault]

At the moment, test coverage are "ok" but still a lot is missing.
We need to through the repo and at least add unittests for uncovered functions to pump those numbers up.

live coverage report:
detail: https://codecov.io/gh/crim-ca/weaver

related issues that will increase such coverage:

• setup functional tests (cwl workflows and application job runs) #3
• functional tests for process deployment #11
• Create WPS3-ADES remote instance for testing #13
• Handle 'default' values and "minOccurs=0" in CWL from WPS-1 #17
• [Test] Chaining sub-workflows #171
• [Feature] Conformance Tests #231
• [Test] Validate resolution of Collection Input data access mechanisms #703
• Increase coverage tests and fixes for weaver.formats utilities #704