Deprecate Twitter::Base#[]

lib/twitter/base.rb

@@ -133,6 +133,7 @@ def initialize(attrs = {})
     #
     # @param method [String, Symbol] Message to send to the object
     def [](method)
+      warn "#{Kernel.caller.first}: [DEPRECATION] #[#{method.inspect}] is deprecated. Use ##{method} to fetch the value."
       send(method.to_sym)
     rescue NoMethodError
       nil

spec/twitter/base_spec.rb

@@ -7,14 +7,26 @@
 
   describe '#[]' do
     it 'calls methods using [] with symbol' do
-      expect(@base[:object_id]).to be_an Integer
+      capture_warning do
+        expect(@base[:object_id]).to be_an Integer
+      end
     end
     it 'calls methods using [] with string' do
-      expect(@base['object_id']).to be_an Integer
+      capture_warning do
+        expect(@base['object_id']).to be_an Integer
+      end
     end
     it 'returns nil for missing method' do
-      expect(@base[:foo]).to be_nil
-      expect(@base['foo']).to be_nil
+      capture_warning do
+        expect(@base[:foo]).to be_nil
+        expect(@base['foo']).to be_nil
+      end
+    end
+    it 'outputs a warning' do
+      warning = capture_warning do
+        @base[:object_id]
+      end
+      expect(warning).to match(/\[DEPRECATION\] #\[:object_id\] is deprecated. Use #object_id to fetch the value./)
     end
   end