When running rake test tasks that populate the test DB for the first time, they fail for me with:

11:29 $ rake test:integration
API controllers newer than Apipie cache! Run apipie:cache rake task to regenerate cache.
rake aborted!
ActiveRecord::RecordInvalid: Validation failed: Value is invalid
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/validations.rb:79:in `raise_record_invalid'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/validations.rb:43:in `save!'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/attribute_methods/dirty.rb:29:in `save!'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/transactions.rb:291:in `block in save!'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/transactions.rb:351:in `block in with_transaction_returning_status'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/test_after_commit-1.1.0/lib/test_after_commit/database_statements.rb:11:in `block in transaction'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:211:in `transaction'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/test_after_commit-1.1.0/lib/test_after_commit/database_statements.rb:5:in `transaction'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/transactions.rb:220:in `transaction'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/transactions.rb:348:in `with_transaction_returning_status'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/activerecord-4.2.6/lib/active_record/transactions.rb:291:in `save!'
/home/dcleal/.rvm/gems/ruby-2.3.0@foreman/gems/protected_attributes-1.1.3/lib/active_record/mass_assignment_security/validations.rb:17:in `create!'
/home/dcleal/code/foreman/foreman/app/models/setting.rb:185:in `create!'
/home/dcleal/code/foreman/foreman/app/models/setting/general.rb:26:in `block (2 levels) in load_defaults'
/home/dcleal/code/foreman/foreman/app/models/setting/general.rb:26:in `each'
/home/dcleal/code/foreman/foreman/app/models/setting/general.rb:26:in `block in load_defaults'

This happens when my host doesn't have an FQDN/domain configured:

11:29 $ ruby -rfacter -e 'puts Facter.value(:domain).inspect'
nil

There's support from #3946 to define a default domain and FQDN in config/settings.yaml, but since tests use config/settings.yaml.test (#11056), this requires editing this source controlled test file.

The fqdn/domain settings can just be added to this file so we have sensible defaults for hosts without an FQDN or domain to run tests. The values don't much matter as fixtures will take over for tests themselves.