Update rubocop / Introduce rubocop-performance, rubocop-minitest (#123)

* Update rubocop

* NewCops: enable

```
Please also note that can also opt-in to new cops by default by adding this to your config:
  AllCops:
    NewCops: enable
```

* Add rubocop-performance

* Fix rubocop-preformance offenses

* Introduce rubocop-minitest

* Fix rubocop-minitest offenses with `rubocop -a`

Author: toshimaru

.rubocop.yml

@@ -1,11 +1,15 @@
 AllCops:
   TargetRubyVersion: 2.4
+  NewCops: enable
   Exclude:
     - "*.gemspec"
     - "gemfiles/*"
     - "vendor/**/*"
     - Rakefile
     - Gemfile
+require:
+  - rubocop-performance
+  - rubocop-minitest
 
 Metrics/MethodLength:
   Enabled: false

Gemfile

@@ -7,5 +7,7 @@ gem 'minitest-reporters'
 gem 'minitest'
 gem 'pry'
 gem 'rake'
-gem 'rubocop', '~> 0.81'
+gem 'rubocop-minitest'
+gem 'rubocop-performance'
+gem 'rubocop'
 gem 'simplecov', '~> 0.17.1'

test/parser/test_inject_anchors_filter.rb

@@ -18,6 +18,6 @@ def test_injects_anchors_into_content
   def test_does_not_inject_toc
     html = @parser.inject_anchors_into_html
 
-    assert_nil(/<ul class="section-nav">/ =~ html)
+    refute_includes(html, %(<ul class="section-nav">))
   end
 end

test/parser/test_ordered_list.rb

@@ -8,19 +8,19 @@ class TestOrderedList < Minitest::Test
   def test_default_configuration
     configuration = Jekyll::TableOfContents::Configuration.new({})
 
-    assert_equal configuration.ordered_list, false
+    refute(configuration.ordered_list)
   end
 
   def test_disabled_ordered_list
     configuration = Jekyll::TableOfContents::Configuration.new('ordered_list' => false)
 
-    assert_equal configuration.ordered_list, false
+    refute(configuration.ordered_list)
   end
 
   def test_enabled_ordered_list
     configuration = Jekyll::TableOfContents::Configuration.new('ordered_list' => true)
 
-    assert_equal configuration.ordered_list, true
+    assert(configuration.ordered_list)
   end
 
   def test_basic_ordered_list_top_heading
@@ -57,7 +57,7 @@ def test_ordered_list_subheadings_with_classes_nested_structure
 
     occurrences = html.scan(/<ol class="sublist-class">/).count
 
-    assert_equal occurrences, 5
+    assert_equal(5, occurrences)
   end
 
   private

test/parser/test_toc_only_filter.rb

@@ -12,12 +12,12 @@ def setup
   def test_injects_toc_container
     html = @parser.build_toc
 
-    assert_match(/<ul class="section-nav">/, html)
+    assert_includes(html, %(<ul class="section-nav">))
   end
 
   def test_does_not_return_content
     html = @parser.build_toc
 
-    assert_nil(%r{<h1>Simple H1</h1>} =~ html)
+    refute_includes(html, %(<h1>Simple H1</h1>))
   end
 end

test/test_configuration.rb

@@ -6,24 +6,24 @@ class TestConfiguration < Minitest::Test
   def test_default_configuration
     configuration = Jekyll::TableOfContents::Configuration.new({})
 
-    assert_equal configuration.toc_levels, 1..6
-    assert_equal configuration.ordered_list, false
-    assert_equal configuration.no_toc_section_class, 'no_toc_section'
-    assert_equal configuration.list_class, 'section-nav'
-    assert_equal configuration.sublist_class, ''
-    assert_equal configuration.item_class, 'toc-entry'
-    assert_equal configuration.item_prefix, 'toc-'
+    assert_equal(1..6, configuration.toc_levels)
+    refute(configuration.ordered_list)
+    assert_equal('no_toc_section', configuration.no_toc_section_class)
+    assert_equal('section-nav', configuration.list_class)
+    assert_equal('', configuration.sublist_class)
+    assert_equal('toc-entry', configuration.item_class)
+    assert_equal('toc-', configuration.item_prefix)
   end
 
   def test_type_error
     configuration = Jekyll::TableOfContents::Configuration.new('TypeError!')
 
-    assert_equal configuration.toc_levels, 1..6
-    assert_equal configuration.ordered_list, false
-    assert_equal configuration.no_toc_section_class, 'no_toc_section'
-    assert_equal configuration.list_class, 'section-nav'
-    assert_equal configuration.sublist_class, ''
-    assert_equal configuration.item_class, 'toc-entry'
-    assert_equal configuration.item_prefix, 'toc-'
+    assert_equal(1..6, configuration.toc_levels)
+    refute(configuration.ordered_list)
+    assert_equal('no_toc_section', configuration.no_toc_section_class)
+    assert_equal('section-nav', configuration.list_class)
+    assert_equal('', configuration.sublist_class)
+    assert_equal('toc-entry', configuration.item_class)
+    assert_equal('toc-', configuration.item_prefix)
   end
 end

test/test_toc_tag.rb

@@ -17,7 +17,7 @@ def test_toc_tag
       site: @stubbed_context1.new({ 'toc' => nil })
     )
     tag = Jekyll::TocTag.parse('toc_tag', '', Tokenizer.new(''), ParseContext.new)
-    assert_equal tag.render(context), "<ul class=\"section-nav\">\n<li class=\"toc-entry toc-h1\"><a href=\"#test\">test</a></li>\n</ul>"
+    assert_equal("<ul class=\"section-nav\">\n<li class=\"toc-entry toc-h1\"><a href=\"#test\">test</a></li>\n</ul>", tag.render(context))
   end
 
   def test_toc_tag_returns_empty_string