add specs

spec/services/auto_rotate_service_spec.rb

@@ -1,14 +1,32 @@
 RSpec.describe AutoRotateService do
   let(:image) { file_fixture("image-rotated.jpg") }
+  let(:image_no_exif) { file_fixture("image-no-exif.jpg") }
+  let(:image_no_rotation) { file_fixture("image-no-rotation.jpg") }
   let(:auto_rotate_service) { AutoRotateService.new }
 
   describe '#process' do
     it 'returns a tempfile if auto_rotate succeeds' do
       Tempfile.create do |output|
-        auto_rotate_service.process(image, output)
+        result = auto_rotate_service.process(image, output)
         expect(MiniMagick::Image.new(image.to_path)["%[orientation]"]).to eq('LeftBottom')
         expect(MiniMagick::Image.new(output.to_path)["%[orientation]"]).to eq('TopLeft')
-        expect(output.size).to be_between(image.size / 1.2, image.size)
+        expect(result.size).to be_between(image.size / 1.2, image.size)
+      end
+    end
+
+    it 'returns nil if image does not need to be return' do
+      Tempfile.create do |output|
+        result = auto_rotate_service.process(image_no_rotation, output)
+        expect(MiniMagick::Image.new(image_no_rotation.to_path)["%[orientation]"]).to eq('TopLeft')
+        expect(result).to eq nil
+      end
+    end
+
+    it 'returns nil if no exif info on image' do
+      Tempfile.create do |output|
+        result = auto_rotate_service.process(image_no_exif, output)
+        expect(MiniMagick::Image.new(image_no_exif.to_path)["%[orientation]"]).to eq('Undefined')
+        expect(result).to eq nil
       end
     end
   end