Check if Rails is fully initialized

lib/saml_idp.rb

@@ -9,7 +9,7 @@ module SamlIdp
   require 'saml_idp/metadata_builder'
   require 'saml_idp/version'
   require 'saml_idp/fingerprint'
-  require 'saml_idp/engine' if defined?(::Rails)
+  require 'saml_idp/engine' if defined?(::Rails::Engine)
 
   def self.config
     @config ||= SamlIdp::Configurator.new

lib/saml_idp/configurator.rb

@@ -35,7 +35,7 @@ def initialize
       self.service_provider.persisted_metadata_getter = ->(id, service_provider) {  }
       self.session_expiry = 0
       self.attributes = {}
-      self.logger = defined?(::Rails) ? Rails.logger : ->(msg) { puts msg }
+      self.logger = (defined?(::Rails) && Rails.respond_to?(:logger)) ? Rails.logger : ->(msg) { puts msg }
     end
 
     # formats

spec/lib/saml_idp/configurator_spec.rb

@@ -47,5 +47,34 @@ module SamlIdp
     it 'has a valid session_expiry' do
       expect(subject.session_expiry).to eq(0)
     end
+
+    context "logger initialization" do
+      context 'when Rails has been properly initialized' do
+        it 'sets logger to Rails.logger' do
+          stub_const("Rails", Class.new)
+          allow(Rails).to receive(:respond_to?).with(:logger).and_return(true)
+          allow(Rails).to receive(:logger).and_return(double("Rails.logger"))
+
+          expect(subject.logger).to eq(Rails.logger)
+        end
+      end
+
+      context 'when Rails is not fully initialized' do
+        it 'sets logger to a lambda' do
+          stub_const("Rails", Class.new)
+          allow(Rails).to receive(:respond_to?).with(:logger).and_return(false)
+
+          expect(subject.logger).to be_a(Proc)
+        end
+      end
+
+      context 'when Rails is not defined' do
+        it 'sets logger to a lambda' do
+          hide_const("Rails")
+
+          expect(subject.logger).to be_a(Proc)
+        end
+      end
+    end
   end
 end