Prefer to_s over string interpolation

lib/omniauth/builder.rb

@@ -49,7 +49,7 @@ module OmniAuth
         middleware = klass
       else
         begin
-          middleware = OmniAuth::Strategies.const_get("#{OmniAuth::Utils.camelize(klass.to_s)}")
+          middleware = OmniAuth::Strategies.const_get((OmniAuth::Utils.camelize(klass.to_s)).to_s)
         rescue NameError
           raise(LoadError.new("Could not find matching strategy for #{klass.inspect}. You may need to install an additional gem (such as omniauth-#{klass})."))
         end

spec/omniauth/strategy_spec.rb

@@ -155,7 +155,7 @@ describe OmniAuth::Strategy do
   end
 
   %w(request_phase).each do |abstract_method|
-    context "#{abstract_method}" do
+    context abstract_method.to_s do
       it 'raises a NotImplementedError' do
         strat = Class.new
         strat.send :include, OmniAuth::Strategy