finished tests for environment

added test for pupetclass

added the host_parameter_test, modified the Ensure_not_use_by issue in the subnet model and almost finished the subnet_test

added the domain_parameter_test and group_parameter_test, modified the ensure_not_used_by in subnet model, almost finished the domain test and started the subnet test.

first host_mailer tests to complete

modified the Ensure_not_use_by in Domain model, started the Domain test, and corrected some minor issues in Auth_source_ldap test

added test for before_destroy on architecture

before_destroy patch successfully applied, also, added require for ruby-debug

added hostgroup test and fixed some assertions

refactored the trailing spaces test and added parameter test