## Motivation:
There is no way to run code statically like in Obj-C using `+ [NSObject initialize]`, so this ensures (through a new `SwiftLint` rule) that all test classes inherit this common test class instead of `XCTestCase` directly.
A future PR will make use of this new `CIRCLECI_TESTS_GENERATE_SNAPSHOTS` environment variable to allow regenerating snapshots in CI.
I've also moved the duplicated `CurrentTestCaseTracker` usages to a single point.
This is duplicated in most of the `NetworkOperation`s. This new shared implementation will be used by `HTTPClient`.
For #695.
See #1429 for how this is used.
* moved test suites to Tests folder
* fixed outdated path
* fixed more outdated paths
* moved TestsPlans to Tests folder
* update path to Constants.swift
NachoSoto