Optimize rspec tests

[fatkodima]

Did a simple profiling of rspec tests.
Got

TOTAL    (pct)     SAMPLES    (pct)     FRAME
34229  (17.1%)       20146  (10.1%)     Psych::Parser#_native_parse <==========
13387   (6.7%)        7628   (3.8%)     RuboCop::Cop::Registry#cops_for_department
 6845   (3.4%)        6845   (3.4%)     (marking)
 6372   (3.2%)        6372   (3.2%)     (sweeping)
 5304   (2.7%)        5304   (2.7%)     Kernel#`
52086  (26.1%)        5027   (2.5%)     Class#new
 4999   (2.5%)        4999   (2.5%)     String#match?
 8569   (4.3%)        4262   (2.1%)     RuboCop::YAMLDuplicationChecker.traverse
 6471   (3.2%)        4032   (2.0%)     Parser::Lexer#advance
 3533   (1.8%)        3489   (1.7%)     IO.read
 3071   (1.5%)        3071   (1.5%)     File.expand_path

Before, tests run is around 5m15s, after - around 4m20s.