Unit tests for all Flowcb/Accept plugins

[gcglinton]

This is a full test suite for all 23 FlowCB Accept plugins.

• Tests have 100% coverage
  • It might be overkill, but the plugins were (mostly) simple, and getting perfect coverage wasn't much harder than 90+
• Some asserts are less than ideal (checking the number of log messages), as changes to other parts of the code could have negative effects
  • Those asserts could be probably be removed, as I'm generally also checking that a particular message was logged, which is more telling
• Small config change to pytest, in order to ensure that only classes prefixed with Test_ are treated as test classes (default is just Test)

Notable innovations with these tests

• Used Paramaterized tests in with wmotypesuffix_test.py
  • Very simple parameters made this a no-brainer, without having to do a for loop inside the test
  • Other tests might have similar use-cases, so good to have the patter defined
• More mocking examples, mostly with time, and random, but also one with urllib
  • Really handy/important to tightly control the test environment, and get be able to assert on known values
• Extensive use of existing SR3 classes (config, and message), in order to properly build tests
  • It does mean these tests depend on those classes operating properly, but it should be fairly easy to eventually have dependencies set if that was wanted/needed

There's also a couple of late fixes to the actual plugins here, which are required to make them operate as designed

[petersilva]

they will not affect the integration tests, so it should be fine to fix any lingering issues post-merge.