Improve test coverage

[jgarber623]

Currently:

COVERAGE: 100.00% -- 836/836 lines in 45 files
BRANCH COVERAGE:  95.83% -- 92/96 branches in 45 branches

+----------+---------------------------------------------------+-------+--------+---------+-----------------+----------+-----------------+------------------+
| coverage | file                                              | lines | missed | missing | branch coverage | branches | branches missed | branches missing |
+----------+---------------------------------------------------+-------+--------+---------+-----------------+----------+-----------------+------------------+
| 100.00%  | lib/sinatra/param/coercions/array_coercion.rb     | 8     | 0      |         |  50.00%         | 2        | 1               | 10[then]         |
| 100.00%  | lib/sinatra/param/core_ext/enumerable.rb          | 5     | 0      |         |  75.00%         | 4        | 1               | 3[else]          |
| 100.00%  | lib/sinatra/param/coercions/boolean_coercion.rb   | 10    | 0      |         |  83.33%         | 6        | 1               | 10[then]         |
| 100.00%  | lib/sinatra/param/validations/match_validation.rb | 15    | 0      |         |  83.33%         | 6        | 1               | 15[else]         |
+----------+---------------------------------------------------+-------+--------+---------+-----------------+----------+-----------------+------------------+