Improve spec

app/assets/javascripts/copy_as_gfm.js.es6

@@ -3,9 +3,10 @@
 
 (() => {
   const gfmRules = {
-    // Should have an entry for every filter in lib/banzai/pipeline/gfm_pipeline.rb,
-    // in reverse order.
-    // Should have test coverage in spec/features/copy_as_gfm_spec.rb.
+    // The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb convert GitLab Flavored Markdown (GFM) to HTML.
+    // These handlers consequently convert that same HTML to GFM to be copied to the clipboard.
+    // Every filter in lib/banzai/pipeline/gfm_pipeline.rb that generates HTML from GFM should have a handler here, in reverse order.
+    // The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
     InlineDiffFilter: {
       'span.idiff.addition'(el, text) {
         return `{+${text}+}`;

lib/banzai/pipeline/gfm_pipeline.rb

 module Banzai
   module Pipeline
     class GfmPipeline < BasePipeline
-      # Every filter should have an entry in app/assets/javascripts/copy_as_gfm.js.es6,
-      # in reverse order.
-      # Should have test coverage in spec/features/copy_as_gfm_spec.rb.
+      # These filters convert GitLab Flavored Markdown (GFM) to HTML.
+      # The handlers defined in app/assets/javascripts/copy_as_gfm.js.es6 consequently convert that same HTML to GFM to be copied to the clipboard.
+      # Every filter that generates HTML from GFM should have a handler in app/assets/javascripts/copy_as_gfm.js.es6, in reverse order.
+      # The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
       def self.filters
         @filters ||= FilterArray[
           Filter::SyntaxHighlightFilter,

spec/features/copy_as_gfm_spec.rb

@@ -13,17 +13,17 @@ describe 'Copy as GFM', feature: true, js: true do
     visit namespace_project_issue_path(@project.namespace, @project, @feat.issue)
   end
 
-  # Should have an entry for every filter in lib/banzai/pipeline/gfm_pipeline.rb
-  # and app/assets/javascripts/copy_as_gfm.js.es6
-  filters = {
-    'any filter' => [
-      [
-        'crazy nesting',
-        '> 1. [x] **[$`2 + 2`$ {-=-}{+=+} 2^2 ~~:thumbsup:~~](http://google.com)**'
-      ],
-      [
-        'real world example from the gitlab-ce README',
-        <<-GFM.strip_heredoc
+  # The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb convert GitLab Flavored Markdown (GFM) to HTML.
+  # The handlers defined in app/assets/javascripts/copy_as_gfm.js.es6 consequently convert that same HTML to GFM.
+  # To make sure these filters and handlers are properly aligned, this spec tests the GFM-to-HTML-to-GFM cycle
+  # by verifying (`html_to_gfm(gfm_to_html(gfm)) == gfm`) for a number of examples of GFM for every filter.
+
+  it 'supports nesting' do
+    verify '> 1. [x] **[$`2 + 2`$ {-=-}{+=+} 2^2 ~~:thumbsup:~~](http://google.com)**'
+  end
+
+  it 'supports a real world example from the gitlab-ce README' do
+    verify <<-GFM.strip_heredoc
       # GitLab
 
       [![Build status](https://gitlab.com/gitlab-org/gitlab-ce/badges/master/build.svg)](https://gitlab.com/gitlab-org/gitlab-ce/commits/master)
@@ -52,78 +52,96 @@ describe 'Copy as GFM', feature: true, js: true do
 
       - Completely free and open source (MIT Expat license)
     GFM
-      ]
-    ],
-    'InlineDiffFilter' => [
+  end
+
+  it 'supports InlineDiffFilter' do
+    verify(
       '{-Deleted text-}',
       '{+Added text+}'
-    ],
-    'TaskListFilter' => [
+    )
+  end
+
+  it 'supports TaskListFilter' do
+    verify(
       '- [ ] Unchecked task',
       '- [x] Checked task',
       '1. [ ] Unchecked numbered task',
       '1. [x] Checked numbered task'
-    ],
-    'ReferenceFilter' => [
-      ['issue reference', -> { @feat.issue.to_reference }],
-      ['full issue reference', -> { @feat.issue.to_reference(full: true) }],
-      ['issue URL', -> { namespace_project_issue_url(@project.namespace, @project, @feat.issue) }],
-      ['issue URL with note anchor', -> { namespace_project_issue_url(@project.namespace, @project, @feat.issue, anchor: 'note_123') }],
-      ['issue link', -> { "[Issue](#{namespace_project_issue_url(@project.namespace, @project, @feat.issue)})" }],
-      ['issue link with note anchor', -> { "[Issue](#{namespace_project_issue_url(@project.namespace, @project, @feat.issue, anchor: 'note_123')})" }],
-    ],
-    'AutolinkFilter' => [
-      'https://example.com'
-    ],
-    'TableOfContentsFilter' => [
-      '[[_TOC_]]'
-    ],
-    'EmojiFilter' => [
-      ':thumbsup:'
-    ],
-    'ImageLinkFilter' => [
-      '![Image](https://example.com/image.png)'
-    ],
-    'VideoLinkFilter' => [
-      '![Video](https://example.com/video.mp4)'
-    ],
-    'MathFilter' => [
+    )
+  end
+
+  it 'supports ReferenceFilter' do
+    verify(
+      # issue reference
+      @feat.issue.to_reference,
+      # full issue reference
+      @feat.issue.to_reference(full: true),
+      # issue URL
+      namespace_project_issue_url(@project.namespace, @project, @feat.issue),
+      # issue URL with note anchor
+      namespace_project_issue_url(@project.namespace, @project, @feat.issue, anchor: 'note_123'),
+      # issue link
+      "[Issue](#{namespace_project_issue_url(@project.namespace, @project, @feat.issue)})",
+      # issue link with note anchor
+      "[Issue](#{namespace_project_issue_url(@project.namespace, @project, @feat.issue, anchor: 'note_123')})",
+    )
+  end
+
+  it 'supports AutolinkFilter' do
+    verify 'https://example.com'
+  end
+
+  it 'supports TableOfContentsFilter' do
+    verify '[[_TOC_]]'
+  end
+
+  it 'supports EmojiFilter' do
+    verify ':thumbsup:'
+  end
+
+  it 'supports ImageLinkFilter' do
+    verify '![Image](https://example.com/image.png)'
+  end
+
+  it 'supports VideoLinkFilter' do
+    verify '![Video](https://example.com/video.mp4)'
+  end
+
+  it 'supports MathFilter' do
+    verify(
       '$`c = \pm\sqrt{a^2 + b^2}`$',
-      [
-        'math block',
+      # math block
       <<-GFM.strip_heredoc
         ```math
         c = \pm\sqrt{a^2 + b^2}
         ```
       GFM
-      ]
-    ],
-    'SyntaxHighlightFilter' => [
-      [
-        'code block',
-        <<-GFM.strip_heredoc
+    )
+  end
+
+  it 'supports SyntaxHighlightFilter' do
+    verify <<-GFM.strip_heredoc
       ```ruby
       def foo
         bar
       end
       ```
     GFM
-      ]
-    ],
-    'MarkdownFilter' => [
+  end
+
+  it 'supports MarkdownFilter' do
+    verify(
       '`code`',
       '`` code with ` ticks ``',
 
       '> Quote',
-      [
-        'multiline quote',
+      # multiline quote
       <<-GFM.strip_heredoc,
         > Multiline
         > Quote
         >
         > With multiple paragraphs
       GFM
-      ],
 
       '![Image](https://example.com/image.png)',
 
@@ -132,39 +150,36 @@ describe 'Copy as GFM', feature: true, js: true do
       '[Link](https://example.com)',
 
       '- List item',
-      [
-        'multiline list item',
+
+      # multiline list item
       <<-GFM.strip_heredoc,
         - Multiline
           List item
       GFM
-      ],
-      [
-        'nested lists',
+
+      # nested lists
       <<-GFM.strip_heredoc,
         - Nested
 
 
           - Lists
       GFM
-      ],
+
       '1. Numbered list item',
-      [
-        'multiline numbered list item',
+
+      # multiline numbered list item
       <<-GFM.strip_heredoc,
         1. Multiline
           Numbered list item
       GFM
-      ],
-      [
-        'nested numbered list',
+
+      # nested numbered list
       <<-GFM.strip_heredoc,
         1. Nested
 
 
           1. Numbered lists
       GFM
-      ],
 
       '# Heading',
       '## Heading',
@@ -183,38 +198,17 @@ describe 'Copy as GFM', feature: true, js: true do
 
       '-----',
 
-      [
-        'table',
+      # table
       <<-GFM.strip_heredoc,
         | Centered | Right | Left |
         | :------: | ----: | ---- |
         | Foo | Bar | **Baz** |
         | Foo | Bar | **Baz** |
       GFM
-      ]
-    ]
-  }
-
-  filters.each do |filter, examples|
-    context filter do
-      examples.each do |ex|
-        if ex.is_a?(String)
-          desc = "'#{ex}'"
-          gfm = ex
-        else
-          desc, gfm = ex
+    )
   end
 
-        it "transforms #{desc} to HTML and back to GFM" do
-          gfm = instance_exec(&gfm) if gfm.is_a?(Proc)
-
-          html = markdown(gfm)
-          gfm2 = html_to_gfm(html)
-          expect(gfm2.strip).to eq(gfm.strip)
-        end
-      end
-    end
-  end
+  alias_method :gfm_to_html, :markdown
 
   def html_to_gfm(html)
     js = <<-JS.strip_heredoc
@@ -227,6 +221,16 @@ describe 'Copy as GFM', feature: true, js: true do
     page.evaluate_script(js)
   end
 
+  def verify(*gfms)
+    aggregate_failures do
+      gfms.each do |gfm|
+        html = gfm_to_html(gfm)
+        output_gfm = html_to_gfm(html)
+        expect(output_gfm.strip).to eq(gfm.strip)
+      end
+    end
+  end
+
   # Fake a `current_user` helper
   def current_user
     @feat.user