use a new db for every rake spec variant (instead of using TRAVIS_JOB_NUMBER)

Author: mceachen

spec/db/database.yml

@@ -1,5 +1,5 @@
 common: &common
-  database: closure_tree_test<%= ENV['TRAVIS_JOB_NUMBER'].to_s.gsub(/\W/, '_') %>
+  database: <%= db_name %>
   host: localhost
   pool: 50
   timeout: 5000

spec/spec_helper.rb

@@ -13,8 +13,6 @@
 
 Thread.abort_on_exception = true
 
-ENV['TRAVIS_JOB_NUMBER'] ||= rand(1..2**31).to_s
-
 Dir['./spec/support/**/*.rb'].sort.each { |f| require f }
 
 RSpec.configure do |config|

spec/support/database.rb

@@ -12,6 +12,11 @@ def sqlite?
 ActiveRecord::Migration.verbose = false
 ActiveRecord::Base.table_name_prefix = ENV['DB_PREFIX'].to_s
 ActiveRecord::Base.table_name_suffix = ENV['DB_SUFFIX'].to_s
+
+def db_name
+  @db_name ||= "closure_tree_test_#{rand(1..2**31)}"
+end
+
 ActiveRecord::Base.configurations = YAML::load(ERB.new(IO.read("#{database_folder}/database.yml")).result)
 
 config = ActiveRecord::Base.configurations[database_adapter]
@@ -39,8 +44,8 @@ def sqlite?
 def count_queries(&block)
   count = 0
   counter_fn = ->(name, started, finished, unique_id, payload) do
-    count += 1 unless payload[:name].in? %w[ CACHE SCHEMA ]
+    count += 1 unless payload[:name].in? %w[CACHE SCHEMA]
   end
-  ActiveSupport::Notifications.subscribed(counter_fn, "sql.active_record", &block)
+  ActiveSupport::Notifications.subscribed(counter_fn, 'sql.active_record', &block)
   count
 end