fix test dependencies on user directory

keyth.gemspec

@@ -13,7 +13,7 @@ Gem::Specification.new do |s|
   s.homepage    = 'http://rubygems.org/gems/keyth'
   s.license     = 'MIT'
 
+  s.add_development_dependency 'dotenv'
   s.add_development_dependency 'rake'
   s.add_development_dependency 'rspec'
-  s.add_development_dependency 'dotenv'
 end

spec/spec_helper.rb

@@ -1,11 +1,17 @@
 # encoding: utf-8
+require 'fileutils'
+require 'tmpdir'
 require_relative '../lib/keyth'
 
+TESTING_NAMESPACE = 'rspec_testing_only'
+
 def make_temp_store
-  Keyth.namespace('rspec_testing_only')
+  Keyth.namespace(TESTING_NAMESPACE)
+  @dir = Dir.mktmpdir
+  ENV['KEYTH_KEYFILE'] = File.join(@dir, TESTING_NAMESPACE + '.yml')
 end
 
 def destroy_temp_store
-  key_file = File.join(Dir.home, '.keyth', 'rspec_testing_only.yml')
-  File.unlink(key_file) if File.file?(key_file)
+  File.unlink(ENV['KEYTH_KEYFILE']) if File.file?(ENV['KEYTH_KEYFILE'])
+  FileUtils.remove_entry_secure @dir
 end