diff --git a/lib/lgtm/error_handleable.rb b/lib/lgtm/error_handleable.rb
index dfac39a..ab6810a 100644
--- a/lib/lgtm/error_handleable.rb
+++ b/lib/lgtm/error_handleable.rb
@@ -1,21 +1,22 @@
 module Lgtm
+  # ErrorHandleable of module of error handling
   module ErrorHandleable
-    # 2xx http success status.
-    SUCCESS_STATUSES = [Net::HTTPSuccess, Net::HTTPFound]
     # 4xx http status.
-    CLIENT_ERRORS = [Net::HTTPBadRequest, Net::HTTPForbidden, Net::HTTPNotFound]
+    CLIENT_ERRORS = [
+      Net::HTTPBadRequest,
+      Net::HTTPForbidden,
+      Net::HTTPNotFound
+    ].freeze
     # 5xx http status.
     SERVER_ERRORS = [
       Net::HTTPInternalServerError,
       Net::HTTPBadGateway,
       Net::HTTPServiceUnavailable,
-      Net::HTTPGatewayTimeOut,
-    ]
+      Net::HTTPGatewayTimeOut
+    ].freeze
 
     def validate_response(response)
       case response
-      when *SUCCESS_STATUSES
-        # Nothing to do.
       when *SERVER_ERRORS
         raise ::Lgtm::Errors::UnexpectedError
       when *CLIENT_ERRORS
diff --git a/lib/lgtm/plugin.rb b/lib/lgtm/plugin.rb
index f425510..0c074bc 100644
--- a/lib/lgtm/plugin.rb
+++ b/lib/lgtm/plugin.rb
@@ -55,8 +55,7 @@ def fetch_image_url(https_image_only: false)
         return fetch_image_url(https_image_only: true)
       end
       url
-    rescue ::Lgtm::Errors::UnexpectedError
-      nil
+    rescue ::Lgtm::Errors::UnexpectedError; nil
     end
 
     def process_request(url)
diff --git a/spec/lgtm_spec.rb b/spec/lgtm_spec.rb
index 239a0d9..04f4369 100644
--- a/spec/lgtm_spec.rb
+++ b/spec/lgtm_spec.rb
@@ -18,7 +18,12 @@ def mock(request_url: 'https://lgtm.in/p/sSuI4hm0q',
   end
 
   describe '#check_lgtm' do
-    subject { lgtm.check_lgtm(https_image_only: https_image_only, image_url: image_url) }
+    subject do
+      lgtm.check_lgtm(
+        https_image_only: https_image_only,
+        image_url: image_url
+      )
+    end
 
     let(:dangerfile) { testing_dangerfile }
     let(:lgtm) { dangerfile.lgtm }
@@ -42,7 +47,8 @@ def mock(request_url: 'https://lgtm.in/p/sSuI4hm0q',
       end
 
       it 'lgtm with errors' do
-        allow(lgtm).to receive(:validate_response).and_raise(::Lgtm::Errors::UnexpectedError)
+        allow(lgtm).to receive(:validate_response)
+          .and_raise(::Lgtm::Errors::UnexpectedError)
         is_expected
         expect(dangerfile.status_report[:markdowns][0].message)
           .to eq("<h1 align='center'>LGTM</h1>")