あー、この `not` の書き方、僕の環境では通らなかったんですよね。

```
$ bundle exec rake test
/opt/local/bin/ruby1.9 -I"lib:lib:test" -I"/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib" "/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb" "test/plugin/selector.rb" "test/plugin/sql.rb" 
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb:15:in `require': /private/tmp/mohair/test/plugin/sql.rb:25: syntax error, unexpected tIDENTIFIER, expecting '(' (SyntaxError)
      assert(not s[:select].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:25: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:26: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:from].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:26: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:27: syntax error, unexpected tLPAREN_ARG, expecting '('
      assert(not (Mohair.build s).nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:27: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:58: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:select].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:58: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:59: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:from].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:59: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:60: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:where].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:60: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:61: syntax error, unexpected tLPAREN_ARG, expecting '('
      assert(not (Mohair.build s).nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:61: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:73: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:select].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:73: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:74: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:from].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:74: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:75: syntax error, unexpected tIDENTIFIER, expecting '('
      assert(not s[:group_by].nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:75: syntax error, unexpected ')', expecting keyword_end
/private/tmp/mohair/test/plugin/sql.rb:76: syntax error, unexpected tLPAREN_ARG, expecting '('
      assert(not (Mohair.build s).nil?)
                  ^
/private/tmp/mohair/test/plugin/sql.rb:76: syntax error, unexpected ')', expecting keyword_end
	from /private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb:15:in `block in <main>'
	from /private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb:4:in `select'
	from /private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb:4:in `<main>'
rake aborted!
Command failed with status (1): [ruby -I"lib:lib:test" -I"/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib" "/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/rake_test_loader.rb" "test/plugin/selector.rb" "test/plugin/sql.rb" ]
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/testtask.rb:104:in `block (3 levels) in define'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils.rb:45:in `call'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils.rb:45:in `sh'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils_ext.rb:37:in `sh'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils.rb:82:in `ruby'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils_ext.rb:37:in `ruby'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/testtask.rb:100:in `block (2 levels) in define'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/file_utils_ext.rb:58:in `verbose'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/testtask.rb:98:in `block in define'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:246:in `call'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:246:in `block in execute'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:241:in `each'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:241:in `execute'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:184:in `block in invoke_with_call_chain'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:177:in `invoke_with_call_chain'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/task.rb:170:in `invoke'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:143:in `invoke_task'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:101:in `block (2 levels) in top_level'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:101:in `each'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:101:in `block in top_level'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:110:in `run_with_threads'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:95:in `top_level'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:73:in `block in run'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:160:in `standard_exception_handling'
/private/tmp/mohair/vendor/bundler/ruby/1.9.1/gems/rake-10.0.4/lib/rake/application.rb:70:in `run'
Tasks: TOP => test
(See full trace by running task with --trace)
```