Update dependencies.

.rubocop.yml

@@ -1,7 +1,10 @@
 require:
+  - rubocop-minitest
   - rubocop-performance
+  - rubocop-rake
 
 AllCops:
+  NewCops: enable
   Exclude:
     - .git/**/*
 
@@ -16,6 +19,9 @@ Layout/LineLength:
 Layout/SpaceInsideHashLiteralBraces:
   Enabled: false
 
+Metrics/MethodLength:
+  Max: 12
+
 Naming/AccessorMethodName:
   Enabled: false
 

.travis.yml

@@ -3,8 +3,8 @@ sudo: false
 language: ruby
 cache: bundler
 rvm:
-  - 2.6.4
+  - 3.0.0
 jdk:
   - openjdk8
 before_install:
-  - gem install bundler -v 2.0.2
+  - gem install bundler

Rakefile

@@ -1,10 +1,13 @@
 require 'bundler/gem_tasks'
 require 'rake/testtask'
+require 'rubocop/rake_task'
 
 Rake::TestTask.new(:test) do |t|
   t.libs << 'test'
   t.libs << 'lib'
   t.test_files = FileList['test/**/*_test.rb']
 end
 
-task default: :test
+RuboCop::RakeTask.new
+
+task default: %i[test rubocop]

example/run.rb

@@ -64,4 +64,4 @@
 pdf.save_as 'output.flat.pdf', flatten: true
 
 # closing the document
-pdf.close
+pdf.close

fillable-pdf.gemspec

@@ -12,6 +12,7 @@ Gem::Specification.new do |spec|
   spec.description   = 'FillablePDF is an extremely simple and lightweight utility that bridges iText and Ruby in order to fill out fillable PDF forms or extract field values from previously filled out PDF forms.'
   spec.homepage      = 'https://github.com/vkononov/fillable-pdf'
   spec.license       = 'MIT'
+  spec.required_ruby_version = Gem::Requirement.new('>= 2.4.0')
 
   spec.files = Dir.chdir(File.expand_path(__dir__)) do
     `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(example|test|spec|features)/}) }
@@ -20,9 +21,14 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = %w[ext lib]
 
-  spec.add_development_dependency 'bundler', '~> 2.0'
-  spec.add_development_dependency 'minitest', '~> 5.0'
-  spec.add_development_dependency 'rake', '~> 10.0'
+  spec.add_development_dependency 'bundler'
+  spec.add_development_dependency 'minitest'
+  spec.add_development_dependency 'rake'
+  spec.add_development_dependency 'rubocop'
+  spec.add_development_dependency 'rubocop-md'
+  spec.add_development_dependency 'rubocop-minitest'
+  spec.add_development_dependency 'rubocop-performance'
+  spec.add_development_dependency 'rubocop-rake'
 
   spec.add_runtime_dependency 'rjb', '~> 1.6'
 end

lib/field.rb

@@ -6,10 +6,10 @@ class Field
   # between these constants and tries to create the same constant ("A") for both, which causes
   # an annoying warning "already initialized constant Rjb::Com_itextpdf_kernel_pdf_PdfName::A".
   # As long as RJB has not fixed this issue, this warning will remain suppressed.
-  suppress_warnings { PDF_NAME = Rjb.import('com.itextpdf.kernel.pdf.PdfName') }
+  suppress_warnings { PDF_NAME = Rjb.import('com.itextpdf.kernel.pdf.PdfName') } # rubocop:disable Lint/ConstantDefinitionInBlock
 
   BUTTON = PDF_NAME.Btn.toString
   CHOICE = PDF_NAME.Ch.toString
   SIGNATURE = PDF_NAME.Sig.toString
   TEXT = PDF_NAME.Tx.toString
-end
+end

lib/fillable-pdf.rb

@@ -27,8 +27,8 @@ def initialize(file_path)
       @pdf_doc = PDF_DOCUMENT.new @pdf_reader, @pdf_writer
       @pdf_form = PDF_ACRO_FORM.getAcroForm(@pdf_doc, true)
       @form_fields = @pdf_form.getFormFields
-    rescue StandardError => ex
-      raise "#{ex.message} (input file may be corrupt, incompatible, or may not have any forms)"
+    rescue StandardError => e
+      raise "#{e.message} (input file may be corrupt, incompatible, or may not have any forms)"
     end
   end
 

lib/kernel.rb

@@ -6,4 +6,4 @@ def suppress_warnings
     $VERBOSE = original_verbosity
     result
   end
-end
+end