Rails%203%20In%20Action

Classes outside your control
Once you set this configuration option to the User class and attempt to reference
Forem::Engine.user_class again, you assert that it should not raise that
exception C.
When you run this test using bin/rspec spec/configuration_spec.rb, it will fail
with this error:
uninitialized constant Forem::ConfigurationNotSet
This is because your spec is attempting to reference the exception class before you’ve
even defined it! No problem though, you can define this very easily within the lib/
forem.rb file by using this code:
class ConfigurationNotSet < StandardError
end
The StandardError class is used for custom errors within Ruby and serves as a great
base for this exception. If you run bin/rspec spec/configuration_spec.rb, you’ll
see this:
expected Forem::ConfigurationNotSet with
"[error]" but nothing was raised
When you attempt to grab the user_class setting in your test, it’s not raising this
exception when it should. To fix this, you’ll need to redefine the user_class method
on the Forem::Engine class by putting this code underneath the attr_accessor line
in lib/forem/engine.rb:
def self.user_class
error = "Please define Forem::Engine.user_class" +
" in config/initializers/forem.rb"
@user || raise(ConfigurationNotFound, error)
end
Previously, the user_class method would have returned the @user variable whether
or not it was set. In this method, you now define the message that will be shown if this
class variable is not set. After that, if the class variable is set then it will be returned by
this method, and if not then the ConfigurationNotFound exception will be raised,
which seems to be all the criteria needed for your test to pass. Let’s find out by running
bin/rspec spec/configuration_spec.rb now:
1 example, 0 failures
Great! That’s all passing. You’ve now got a class-level user_class method that you can
set up in any applications that use this engine, so that you can notify the engine of the
class that represents users within the application. If this setting is not set by the application
by the time the engine gets around to referencing it, then the Configuration-
NotFound exception will be raised, informing the owner of the application that they
need to set this variable up in config/initializers/forem.rb.
Let’s now set up the User model within your dummy application so that you can
use this setting.
499