SwaggerChecker falls back to a local load

lib/apivore/swagger_checker.rb

@@ -72,12 +72,29 @@ def load_swagger_doc!
 
     def fetch_swagger!
       session = ActionDispatch::Integration::Session.new(Rails.application)
+      body = nil
+      http_error = true
+
       begin
-        session.get(swagger_path)
-      rescue
-        fail "Unable to perform GET request for swagger json: #{swagger_path} - #{$!}."
+        response_code = session.get(swagger_path)
+
+        if response_code == 200
+          http_error = false
+          body = session.response.body
+        end
+      rescue URI::InvalidURIError
+        # http_error is true
       end
-       JSON.parse(session.response.body)
+
+      if http_error
+        begin
+          open(swagger_path) {|file| body = file.read }
+        rescue Errno::ENOENT
+          fail "Unable to perform GET request for swagger json: #{swagger_path} - #{$!}."
+        end
+      end
+
+      JSON.parse(body)
     end
 
     def validate_swagger!

spec/swagger_checker_spec.rb

@@ -0,0 +1,25 @@
+require 'spec_helper'
+
+describe Apivore::SwaggerChecker do
+  describe '#instance_of' do
+    let(:sample_file_path) { File.join(File.dirname(__FILE__), 'data', '01_sample2.0.json') }
+
+    it 'should be able to load the file via ActionDispatch::Integration' do
+      json = nil
+      open(sample_file_path) { |file| json = file.read }
+      response_double = double('response', body: json)
+      session_double = double('integration', response: response_double, get: 200)
+      allow(ActionDispatch::Integration::Session).to receive(:new).and_return(session_double)
+
+      expect { Apivore::SwaggerChecker.instance_for("/random/url.json") }.to_not raise_error
+    end
+
+    it 'should be able to load the swagger file locally' do
+      expect { Apivore::SwaggerChecker.instance_for(sample_file_path) }.to_not raise_error
+    end
+
+    it 'should throw an exception if it is unable to load the file' do
+      expect { Apivore::SwaggerChecker.instance_for('not_found.json') }.to raise_error(RuntimeError)
+    end
+  end
+end