Make tests less flaky and be able to run under Swift 2.2/Xcode 7.3.

[nlutsenko]

• We have some flaky tests, because operations can run faster than we execute on the current thread
• Also, since XCTest APIs is different between 2.2 and 2.1 - we need to wrap name

[codecov-io]

Current coverage is 94.31%

Merging #1 into master will increase coverage by +11.04% as of 346061e

@@            master      #1   diff @@
======================================
  Files            4       8     +4
  Stmts          281     844   +563
  Branches         0       0       
  Methods          0       0       
======================================
+ Hit            234     796   +562
  Partial          0       0       
- Missed          47      48     +1

Review entire Coverage Diff as of 346061e

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