Migrate accessibility rubocop rule LinkHref from dotcom to erblint-github

Migrate accessibility rubocop rule `LinkHref` from dotcom to erblint-github

Author: Adrián Bolonio

config/accessibility.yml

@@ -4,6 +4,9 @@ require:
 GitHub/Accessibility/ImageHasAlt:
   Enabled: true
   StyleGuide: https://github.com/github/rubocop-github/blob/master/guides/image-has-alt.md
+GitHub/Accessibility/LinkHasHref:
+  Enabled: true
+  StyleGuide: https://github.com/github/rubocop-github/blob/master/guides/link-has-href.md
 GitHub/Accessibility/NoPositiveTabindex:
   Enabled: true
   StyleGuide: https://github.com/github/rubocop-github/blob/master/guides/no-positive-tabindex.md

guides/link-has-href.md

@@ -0,0 +1,29 @@
+# GitHub/Accessibility/LinkHasHref
+
+## Rule Details
+
+Links should go somewhere, you probably want to use a `<button>` instead.
+
+## Resources
+
+- [`<a>`: The Anchor element](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a)
+- [Primer: Links](https://primer.style/design/accessibility/links)
+- [HTML Spec: The a element](https://html.spec.whatwg.org/multipage/text-level-semantics.html#the-a-element)
+
+## Examples
+### **Incorrect** code for this rule 👎
+
+```erb
+<%= link_to 'Go to GitHub' %>
+```
+
+```erb
+<%= link_to 'Go to GitHub', '#' %>
+```
+
+### **Correct** code for this rule  👍
+
+```erb
+<!-- good -->
+<%= link_to 'Go to GitHub', 'https://github.com/' %>
+```

lib/rubocop/cop/github/accessibility/link_has_href.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "rubocop"
+
+module RuboCop
+  module Cop
+    module GitHub
+      module Accessibility
+        class LinkHasHref < Base
+          MSG = "Links should go somewhere, you probably want to use a `<button>` instead.".freeze
+
+          def on_send(node)
+            receiver, method_name, *args = *node
+
+            if receiver.nil? && method_name == :link_to
+              if args.length == 1 || (args.length > 1 && args[1].type == :str && args[1].children.first == "#")
+                add_offense(node.loc.selector)
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

test/test_link_has_href.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require_relative "./cop_test"
+require "minitest/autorun"
+require "rubocop/cop/github/accessibility/link_has_href"
+
+class LinkHasHref < CopTest
+  def cop_class
+    RuboCop::Cop::GitHub::Accessibility::LinkHasHref
+  end
+
+  def test_link_has_href_offense
+    offenses = erb_investigate cop, <<-ERB, "app/views/products/index.html.erb"
+      <%= link_to 'Go to GitHub' %>
+    ERB
+
+    assert_equal 1, offenses.count
+    assert_equal "Links should go somewhere, you probably want to use a `<button>` instead.", offenses[0].message
+
+    offenses = erb_investigate cop, <<-ERB, "app/views/products/index.html.erb"
+      <%= link_to 'Go to GitHub', '#' %>
+    ERB
+
+    assert_equal 1, offenses.count
+    assert_equal "Links should go somewhere, you probably want to use a `<button>` instead.", offenses[0].message
+  end
+
+  def test_link_has_href_no_offense
+    offenses = erb_investigate cop, <<-ERB, "app/views/products/index.html.erb"
+      <%= link_to 'Go to GitHub', 'https://github.com/' %>
+    ERB
+
+    assert_equal 0, offenses.count
+  end
+end